First Sony Chromatron 19C-70



Chapter Nine

Only known Sony Chromatron 19C-70 screenshot. This is a digital photo we shot from a Sony tourist handout souvenir booklet.  If anyone has more information, I’d appreciate it.

Published March 24, 2014, amended October 2, 2022, all rights reserved.

I have been interested in alternative color television picture tube technologies developed over the past decades in an attempt to improve on the Federal Communication Commission/RCA color system adopted 1953 in the United States. We don’t think the full story of the Chromatron has been told. We spent several years researching the Chromatron and originally the text and images appeared on several different pages of this Timeline website. Now I decided to merge this information and give the Chromatron it’s own dedicated page. It is not my intention to describe detailed technical data which would require volumes of material to post. Rather, a brief overview follows.


In 1951, Nobel Prize winner Dr. Ernest O. Lawrence, inventor of the Cyclotron from the University of California Berkley, invented the Lawrence Tube in his garage at home.

Chromatic Television Laboratory, a subsidiary of Paramount based in New York City, with an office in Oakland California, was created in part to commercially develop the Lawrence Tube and renamed it the “Chromatron”. The work was done in tight quarters in the Paramount building in the heart of New York City on Broadway, and Oakland, California.

The Lawrence Tube was unique in that it created the color image with one gun and one electron beam. It used no shadow mask, but instead, a grid of fine wires that were placed directly behind the vertically aligned tri-color phosphor stripes on the screen. The wires were charged with high voltage and when the single electron beam passed through the wires, in a type of electronic lens, they were accelerated and deflected onto the red and blue phosphor stripes. The wires were placed behind the red and blue phosphor stripes, so that the green stripe was excited directly.  The phosphor stripes and corresponding wire grid could be placed horizontally as well as vertically. It was observed that when prototype tubes constructed with horizontal phosphor stripes lined up parallel to the horizontal scanning lines, moire interference patterns were reduced. The original Lawrence Tube was conceived to work with both one and three guns. The one gun version received the most attention because of it’s simplicity and potential lower manufacturing costs. Despite the 90% transparency of the wire grid, the one gun version did not achieve acceptable brightness so an inline three gun version was adopted and at the same time the wire grid and phosphor stripes were changed from horizontal to vertical. 398 lines of resolution were achieved.  A three gun Lawrence Tube was brighter then the one gun and the deflection voltage requirement was greatly reduced.  Both types were developed in prototype form. Later prototypes of the one gun version increased the number of wires in the deflection grid which directly reduced the deflection voltage requirement.  The radiation problem was reduced by placing the wires further back from the phosphor stripes, shielded coils and cables which reduced the capacitance (claimed 3 UV/M at 100 feet) and significantly reduced the driving power requirements.  In addition, the output of the three video amplifiers switched the color information to hit each RGB stripe at the precise moments required.  In other words, a keyed operation of the three color stages.  Later, the General Colornetron adopted this approach.  Successor Chromatron tubes experimented with different color phosphors to obtain the correct combination of brightness and persistence.  Finally a rather large copper box or cage was mounted externally to the bell to reduce the remaining radiation from the grid coil.  All this, helped to reduce the RF radiation to acceptable levels and the pictures produced were described as fairly decent and viewable with no visible streaking or stripeing.  When Autometric, formerly Chromatic shut down facilities in Oakland, California in 1957, Dumont took over the operation of assembly and production.  Phosphors deposited on the faceplate were planned instead of silk screening. A second grid of wires was considered to improve beam focusing for a tighter beam spot.

Dr. Lawrence sold a stake to Paramount Pictures Corporation to develop the Lawrence Tube. View one of several  Patents.

By the time all development and patent rights were sold to Sony, Autometric was working on an in-line three gun, post deflection focused CRT, inspired by the work General Electric developed starting in 1954. (Read more about this later in this presentation).

(Later in this article, we show that Sony settled on the three gun Chromatron for the Japanese market).

Courtesy Broadcasting Magazine

Courtesy Broadcasting Magazine

First details about the Lawrence/Chromatron appear in this article from Electronics Magazine, December, 1951. View PDF. Courtesy Electronics Magazine.


Update March 11, 2020: Detailed account of Dr. Lawrence’s Chromatron work, courtesy Joshua Roebke and Physics Today. View PDF.



The above article’s title calls Dr. Lawrence’s work a failure.  Due to RCA’s litigious nature which dominated the American color television market, competition was stymied until an upstart JAPANESE company perfected the Chromatron and renamed it Trinitron. More about this later.

Here is an article from Billboard Magazine, published October 6, 1951, announcing the first Paramount sets incorporating the Chromatron CRT. This same article also announced that the first CBS-Columbia color sets hit the market on September 28, 1951.


Early History

Before delving into the Chromatron, we need to know a bit about early color television history to better understand why the Chromatron was developed.


Color Wars

This was a time when Columbia Broadcasting System (CBS) was working on the mechanical spinning color wheel field sequential color system (see a modern day field sequential color television on PAGE 4A) while Radio Corporation of America (RCA) was working on the electronic compatible Tri Color shadow mask system (required reading, “The 1953 RCA Red Book FCC Petition”) and Color Television Incorporated proposed the line sequential system. During the FCC trials and public demonstrations of these color systems, Chromatic Television Laboratory was invited to demonstrate their Chromatron one gun color tube.

Color Television Development In The United States

Added June 15, 2020.  During the war emergency, color television production was halted, but CBS was producing good color images in their lab. Here, courtesy of the September 22, 1941 issue of Life Magazine, examples of color quality using the field sequential method. Live and televised images. Bear in mind the 79 year old images digitally formatted for reproduction.





The first experimental fully electronic RCA color camera was undergoing private color trials at RCA’s Wardman Park color studio in Washington D.C., 1949. Below is a shot of the monitor at the Wardman Park color studio in 1949 where the demonstrations of the RCA systems would be held for the FCC a few years later. Only two of these cameras were made, and both were in Washington D.C. This ultra rare photo and information is courtesy of Eyes Of A Generation … Television’s Living History and Bill Wells. Visit this site and you will be rewarded with a rich history of early color television.


Courtesy Bill Wells

At this 1950 trial demonstration, from left to right, a one gun color CRT, a black and white CRT and an RCA three gun tri-color CRT. The Chromatron would work with CBS’s system, thereby eliminating the mechanical spinning wheel or drum and it would work with a one or three gun RCA system. It has been reported that this one gun color CRT is an early RCA development model which was later abandoned and RCA then put all their efforts into developing the three gun CRT. During the trials, the Chromatic Chromatron was considered a leading contender.


This is the color image displayed on the RCA three gun tri-color CRT, RCA’s first such prototype, shown during the demonstration, above on the right. All photos  courtesy RCA via Hagley Museum.

A better look at the three receivers on stage.


Courtesy of the David Sarnoff Library, a closer view of the one gun development RCA color television.




Proceedings of the I.R.E. October, 1951

Color television issue, a comprehensive presentation of engineering papers from RCA outlining development work of 5 color CRT candidates prior to RCA selection of the tri-color dot sequential tube as well as an overview with other color articles and a comprehensive discussion of the CBS field sequential system.  We think this will prove interesting to readers of this Chromatron page. Attention is drawn to the one gun RCA page of this PDF.  Thanks to Jerome H. for finding and sharing the published I.R.E. Directory.


Faye Emerson screenshot off RCA experimental television during a later trial to the public.

Posted September 13, 2022

Filling in the gaps of Chromatron history, we recently researched General Electric’s work in developing their version of the Chromaton.  It was called simply “PA” or Post Acceleration CRT.

Work started in 1954 and by late 1956, GE developed a three gun inline post deflection tube with a wire grid and vertical phosphor stripes.  The wire grid was charged with 7KV and the screen was at 25KV.  The design was easy to deflect and converge, but GE encountered difficulty in aligning the grid wires with the phosphor stripes.  Additionally, the back scattering of secondary electrons created haze.  The haze problem was later ameliorated.  Unfortunately this tube never went into production.  Thank you John Atwood for releasing the documents of Avon C. Campbell, a life long engineer at General Electric.  Later in 1966, the world’s first 3 gun, in-line cathode ray tube went into production as the GE “Porta Color”.  See the Porta Color here.

As a side note: Westinghouse worked on this approach with a prototype 20 inch PA CRT.  We also learned that RCA tested the GE one gun PA and said to have “reservations”.  RCA avoided at great cost, paying royalties to its competitors (think about the Philo Farnsworth litigation).  RCA and GE were closely intertwined by cross licenses.  Being cynical, perhaps the above described RCA one gun color tube was a GE design?

We have extracted the relevant discussions by the General Electric engineering department pertaining to the PA color CRT.


Evaluation by General Electric of their own development CRT.


Summery and recommendations.


Internal General Electric engineering department photos.




January, 1954

General Electric focused on five competitive systems and in the end, decided to contribute development to the Apple Super-Index system as the most viable cost effective technology to compete with RCA’s tri-color shadow mask CRT.

Back to CBS.

THE CBS SYSTEM was approved first by the FCC on October 10, 1950. In public viewing tests, it was deemed to have the best color reproduction, particularly the flesh tones. These first television sets were sold to receive the very limited color programming available. Then the war effort in Korea caused the suspension of production of CBS television sets. Back in the lab, RCA continued development, greatly improving their color system and their biggest advantage was that black and white telecasts could be viewed on the Compatible RCA color system sets. The CBS system required an adaptor to watch color telecasts when black and white dominated television programming at that time. See this article to get insights on the “color war” between CBS and RCA.

Author commentary:  Looking back, CBS had the advantage, but failed to exploit the resources of time, color superiority and lower cost of the field sequential system.  They could simply roll out the inexpensive adaptors for all existing black and white sets without the necessity of buying a new color set.  The first CBS color set sold for $495.00, not $1175, $1295, or $995.  CBS was unprepared to launch the new color system and marketing and education of the public were lacking.  RCA lobbied, litigated and cajoled against the CBS system as they previously did with Farnsworth, Aiken, Philco and others.  Later you will learn how the mechanical field sequential color system developed into a fully electronic system long after the color wars were settled.  What might have been?

More reading. Who Really Invented Electronic Television?


Color converter for black and white television, courtesy Popular Science Magazine.

This circular disk houses the tri-color, RGB color wheel. It rotates at a specified high speed which causes the brain to trick the viewer in seeing full color images. The adaptor could be mounted on most monochrome television receivers in use. This device was created in 1950 and cost between $75. to $100.  There were at least six versions available from other manufactures.  In 1951 a CBS/Columbia color receiver  incorporated the color disc, motor and associated parts within the television cabinet to avoid the clumsy external converter apparatus.  (See a unique twist on this technology at the bottom of the page, here.)


Later, the proponents of the CBS system incorporated the mechanics of the color converter physically into the cabinets of monochrome television receivers, eliminating the bulky apparatus. CBS-Columbia 12CC2 Field Sequential Color Receiver below.  This set went to market for $495.00, half the price of the upcoming Admiral, Westinghouse and RCA color models.  About 100 sets were made in the pilot run and 1000 more shipped out to dealers.  CBS sought to have all recovered for destruction after the collapse of field sequential color system and all but 10 to 12 were recovered.  Source: Bob Cooper, must read.

CBS-Columbia 12CC2 Field Sequential Color Receiver (1951) courtesy Ed Reitan

Update, May 17, 2017

In this article published by Life Magazine February 27, 1950, we can see the superiority of the CBS system in the comparison photos, even though the colors have faded over 67 years.


Courtesy Life Magazine

UPDATE, MAY 17, 2018

Found this interesting cover page (source anonymous) from the Sunday News, New York’s picture newspaper, January 28, 1951. The image depicts the upcoming launch of CBS television color programming. The television shown is a field sequential monitor.


In February, 1951 at the National Photographic show held in New York, these screenshots were taken by amateur photographers and preserved on photographic film. The color images appear to have been shot off a Gray Research field sequential studio monitor. They are some of the very first color television images seen by the public.



The artifacts appearing in the above screenshots were introduced by the scanning process and not the television. They are not present in the direct magazine reproduction. All photos courtesy of Popular Photography magazine.


THE FIRST COLOR telecast was a program called “Premiere” on June 25, 1951.
“Premiere” aired from 4:35 to 5:34 p.m. but only reached five cities: New York, Boston, Philadelphia, Baltimore and Washington, D.C. It has been reported that there were only 30 color sets in operation to view this first telecast. The network stated some 40 thousand viewers watched the telecast. Obviously overstated as conventional black and white sets were not capable of displaying color unless an adaptor was attached to the sets.

Here, courtesy of Life/ are a few select television screen shots taken from an unknown color field sequential receiver during the first week of color telecasting in the United States as published in Life Magazine on July 23, 1951.

Update, December 20, 2016

From Steve D.

“Hi Marshall, In response to your question. The attached photo shows a Gray Research monitor in use on the CBS studio floor during their 1st field sequential color broadcast “Premier” in June 1951. This photo along w/the Gray monitors CBS provided for off screen photos may indicate what color monitors CBS generally used during that time.

-Steve D.”


I now think we can say the following screenshots were taken from a Cray Research monitor. Thanks Steve.







Update, December 21, 2016

From Wayne B. at VideoKarma forums: “Here are some attempts at correcting some of the published slides.
In each case, there’s the original faded slide, then a version with levels corrected in Photoshop. Finally, there’s a version with the levels corrected plus a hue correction. The success of the hue correction on the test pattern and Bisquik box indicates to me that CBS did indeed have a hue shift problem due to lag in the image orthicon, as the color sequence was RBG, and red is shifted toward blue, yellow towards red, green toward yellow (not so obvious) and blue toward green.

I used a “levels” correction layer and clicked on the background of the Bisquick set with the “gray” eyedropper. This over-exposed the slides a bit, so I added a lower (preceding) levels adjustment layer to bring down the levels so the highlights were not overexposed/clipped. I then added a hue/saturation adjustment layer on the top of the stack and adjusted the hue by 20 degrees, which may be a little too much. However, because of film characteristics, it may be impossible to get exactly correct results in the highlights as well as the mid tones. The Doublemint and Couple images seemed to especially need the first over-all level adjustment, as they appear a bit over-exposed and washed out to start with.

The color blockiness in the original scans due to the jpeg compression was emphasized in the yellow when I made the hue adjustment. This is because the Photoshop hue adjustment rotates the proportions of red, green, and blue, which means the brightness also changes when the hue is changed. Maybe working in Lab space instead of RGB space would fix this – I haven’t tried it.

Please feel free to use these images on your site.” Thanks Wayne.

The next day, June 26, 1951, an article appearing in the Milwaukee Journal describes reactions to this first television color cast. The article explains how fifty thousand people may have seen this first color telecast.

Courtesy Milwaukee Journal

Courtesy Milwaukee Journal

By March 30, 1953, the Chairman, Dr. Baker of the National Television System Committee (NTSC), considered the RCA and Chromatic tri-color tubes the most promising, but held out belief that a third tube might surface combining the best of these two tubes.

Courtesy Broadcasting Magazine

Courtesy Broadcasting Magazine


RCA resubmitted their application of the compatible dot sequential electronic system to the FCC and they reversed their 1950 decision, approving the RCA system on December 17, 1953.image (see the excellent 37 page brochure with beautiful photography prepared by RCA Department of Information, published December, 1953, courtesy KRIS TREXLER)

RCA manufactured and sold their first color television in April, 1954, the CT-100 with a 15 inch color tube, (12.5 inch viewable) using the phosphor dot/shadow mask tube. Sales were dismal, lack of color programming, the viewing screen was too small, (12 1/2 inches) and the set was too expensive. It was estimated that RCA manufactured about 4400 CT-100’s. On August 8, 1954, RCA dropped the price of the CT 100 to $495.00 and rebated $505.00 to all who purchased the set.


This advertisement appeared in most major markets across the country about the same day in April, 1954 announcing the availability of the RCA CT-100.

May 2, 1954

RCA announces first public showing in New York City.

The festival marks the introduction in New York City of RCA Victor’s first commercial compatible color television receiver, the CT 100”.

A photo of RCA Exhibition Hall, May, 1954.  Look closely at the sign.

This was the next 19 inch RCA “CT 100”, photo curtesy the Estate of Ed Reitan.

It was designed to compete with the Motorola 19 inch color set under development, then quietly dropped from introduction when RCA learned of the CBS 19 inch curved screen color CRT being developed and subsequent production.

The industry was gearing up for the upcoming Motorola 19 inch color set and RCA’s new 21 inch set.

RCA licensed their 15 inch color tube to other manufactures such as Admiral and Westinghouse shown below, in an effort to promote the fledgling color television industry. A race to introduce the first compatible, electronic color television ensued.

First all electronic color television is offered for sale.

DECEMBER 18, 1953 New Castle News, New Castle, Pennsylvania.

“GEORGE BROS. will allow you full purchase price on an Admiral Color TV purchased anytime between now (December 18, 1953 date of advertisement) and June 1, 1954.”

We believe Admiral offered their dealerships incentives to allow customers full purchase price trade-in’s on expensive Admiral color sets. We found several similar advertisements like this one. Admiral may have been taking advance orders on the C1617A and it’s possible they may have taken orders on this date. This advertisement appears to be an offer to sell (for future delivery) on December 18, 1953.


THIS IS THE FIRST all electronic color set, the Admiral C1617A which was introduced to the public as early as December 18, 1953 according to the Admiral Corporation or on December 30, 1953 according to the New York Times and others.

Courtesy Television History-The First 75 years

Admiral C1617A Courtesy Television History-The First 75 years

Admiral C1617A photos, courtesy of Bruce Buchannan, Early Television Foundation and John Folsom.

Read more about the Admiral C1617 here.

The second color set to go on sale was this Westinghouse H840CK15 on February 28, 1954 in the New York area. There are conflicting sources saying the set went on sale in March, 1954. February 28, 1954 was a Sunday, and stores were closed and so the argument goes that the public would not have access to purchase until the next day, Monday, March 1, 1954. Sunday shopping didn’t start until the mid 1970’s. This particular set was found in Phoenix and offered for sale in 2013. Photo by this author. We passed on this set, but later acquired the set in 2018. You can see the restoration underway here.


Westinghouse H840CK15 photographed March 17, 2013

Westinghouse H840CK15 photographed March 17, 2013


One of the constant complaints of the RCA system used in these first color sets, was the very dim color. One had to turn the lights down and draw the drapes in their homes to see the image clearly. Another problem, color fringing on black and white programs and blurred images with color. This is why the Chromatron (and other systems such as the Apple tube by Philco) were proposed. The RCA system used a metal sheet with many perforations or holes as a color selection method. This was called the shadow mask. The early RCA television tubes with shadow mask blocked 85% of the light from the three electron beams causing a dim image. The original Lawrence Tube only absorbed 14% of the single electron beam light energy, or 86% efficient.

Chromatron PDF

Chromatron PDF


In other words, the wire grid was much more transparent and this tube was as bright as a conventional black and white television of the time. Another big advantage of the Chromatron tube was in theory, it had perfect registration with no convergence requirements because it used just one gun. The Chromatron was said to be less expensive to manufacture, used fewer parts, smaller and lighter.


On June 2, 1953, the first color television telecast in England was conducted using an experimental field sequential system developed by Pye and Chromatic Television laboratory.image Televisions with Chromatron tubes were set up in a children’s hospital to view the coronation of Queen Elizabeth II. The New York Times reported that a Chromatic representative concluded the test was a complete success. Newspaper clip courtesy of the Tipton Tribune, Indiana, June 2, 1953

An account of coronation day and the first color television event as reported by ALEXANDRA PALACE TELEVISION SOCIETY:

“As befits the coming generation, two hundred children saw the Coronation procession by the TV of the future – in colour. They were at the Great Ormand Street Hospital in London. By closed-circuit they received pictures from three TV colour cameras overlooking Parliament Square.”

Recollection of Peter Ward as published in THE 1953 CORONATION OB PETER WARD, GUILD OF TV CAMERAMANS MAGAZINE SPRING l985.

“Whilst 20 million viewers watched the transmission in black and white, 150 children and staff of the Hospital for Sick Children in Great Ormond Street watched part of the procession in colour. Pye of Cambridge were given permission to set up three colour cameras on the roof of the Foreign Office, and by using a portable transmitter beamed the signal to Ormond Street to display colour pictures on two 20″ sets. Twenty years later it would be standard practice for major OBs to be in colour. and today it is common place to deploy 20 to 25 cameras just for one programme ‘Match of the Day’ ”

Re-printed, from his 1985 contribution to the GTC magazine. Peter sent this to match with the transmission on Friday 9th Jan 2004 of “Days That Shook The World”, with a recreation of the BBC 1953 Coronation broadcast complete with period gallery and Marconi Mk 2 camera, done by Dicky Howett of Golden Age TV.

Hull family watching the coronation, presumably on a black and white television as televised by the BBC, courtesy Manchester Central Library, Arts Library, News Chronicle Collection.


With permission from the Los Angles Times, an article appearing July 12, 2015:


Pye demonstrates color television at Radiolympia in 1949, then tests the first experimental field sequential color camera and Chromatron television receiver using the 405 line system.  The telecast was a closed circuit broadcast of the 1953 Queen Elizabeth II coronation.

Photos courtesy of

This photo and caption is courtesy of the Early Television Foundation. Note the very close similarity  to the above photo.


This photo documents the zoom lens used to televise the broadcast in the United Kingdom.


UPDATE, MAY 31, 2021

This may be a Pye experimental field sequential Chromatron color television, using Chromatic Laboratories’s chassis, being the same television as demonstrated at the children’s hospital on June 2, 1953.

The caption for this photo, “British family watching experimental color television” published in the 1954 book, Colour TV: When and How.

English television announcer Sylvia Peters. Original Publication: Picture Post – 7077 – Colour TV: When And How – pub. 1954 (Photo by Raymond Kleboe/Getty Images)


Here is a 1953 specification sheet from Chromatic Television laboratory.

Courtesy Early Television Foundation

Courtesy Early Television Foundation

Update September 2, 2014: Here is a Chromatron Trade PDF by Chromatic Televisions Laboratory Inc., courtesy of the Smithsonian Museum of American History. On page 10, this author learned for the first time that Chromatic was developing beam index CRT’s as well. We annotated the text where this information appears. The PDF file is reversed starting with page 27. Just scroll down to page 1. View PDF.



In the January and February, 1954 issues of International Projectionist magazine, an article describes the three leading color CRT’s, the Lawrence tube, the CBS-Hytron and the RCA three gun, shadow mask tube. Even though the RCA system had just been adopted as the new color standard television system in the United States, the author of the article considered the Chromatron or Lawrence tube the most promising of the three tubes under consideration, for mass production and other reasons. Read this PDF article to learn why and the 8 advantages claimed by the inventor and the author of the article.

Posted December 28, 2015

An article about the Chromatron tube appearing in Radio & Television News, March, 1954. Tap on image for the PDF article.


So why did the Chromatron tube fail to enter the marketplace and gain traction? We will try to answer those questions as we continue.

February, 1954

On the cover of Tele-Tech Magazine, February, 1954, final inspection of Chromatron tubes by Chromatic Labs prior to shipment.

Posted October 2, 2022

Muntz color Chromatron televisions on assembly line. The sets have working images on their screens. March, 1954, curtesy Radio & Television News.

March 22, 1954
Westinghouse was working on a one gun color CRT as disclosed by the the next two articles.


June, 1954

Notice the the perfectly flat and rectangular viewing screen of the Chromatron. Article courtesy Broadcast Magazine.


ONE OF Paramount’s interest in the Chromatron was for use with a pay TV system in hotels. In June, 1954, a test was done at the Park Sheraton hotel in New York City and 1600 guest rooms were hooked up using the Chromatron with the Telemeter coin set top box.

In a July 10, 1954 Billboard magazine article, it was reported that Chromatic Television Laboratory expected to release a 21 inch, one-gun Chromatron in early 1955 under the Chromatic label. Crosley was licensed to manufacture the set domestically and Philips of Holland had the international license.

Courtesy Tele-Tech December, 1953

Courtesy Tele-Tech December, 1953

Courtesy Tele-Tech November, 1956

Courtesy Tele-Tech November, 1956

Chromatic handled the basic development of the Chromatron and then about August, 1957, split the project in two sections, Du Mont in New Jersey was licensed for commercial picture tube fabrication and Lytton Industries in Emeryville, California for the military.

The original Lawrence Tube had 800 vertical phosphor stripes, 400 of which were green. The red and blue stripes were twice as wide as the green to equalize the color across the screen. Chromatic was working to increase the resolution by adding more vertical phosphor stripes. At first, 1000 stripes, later, a development CRT increased to 1600 stripes. Notice the design change in the photo above, the mass has been reduced and the tube takes on a modern appearance.

An article from April, 1956 reviewing a public demonstration of the Chromatron CRT courtesy J. Halphen.


April 15, 1956

Telechrome Inc. displayed a 22 inch Chromatron television receiver, model 311-BR at the NARTB convention held in Chicago, April 15-19, 1956. We have no photos so far.


Courtesy Broadcasting Magazine

At about 1960, Chromatic was renamed Autometric Corporation (source Sy Yusem) and moved to an industrial-type building on the West side of New York city where one floor was devoted to picture tube development and another floor was for the electronics. Up to this point, neither Paramount, Chromatic/Autometric, Crosley, Philips, Du Mont, Lytton, Muntz, General Electronics, Telechrome Inc., Avco, Rayathon, General Electric and others, reportedly developing Chromatron, had successfully developed a Chromatron receiver for the home consumer market.


Now I digress from the story temporally to tell you about Julius Shapiro, who I discovered after reading this story “THE WONDROUS LIVES OF JULIUS SHAPIRO” by Laurie Gwen Shapiro an Emmy-nominated documentary filmmaker as well as a novelist. She is currently working on her first non-fiction book, about a Lower East Side teen stowaway on Commander Byrd’s 1928 expedition to Antarctica. (Simon & Schuster)

Utterly fascinated, I looked up Laurie’s phone number and called her. She answered on the first try. I was hoping to find more information about her fathers involvement with the Chromatron project. A stranger was calling and yet she accepted me enthusiastically and all my questions. I learned that her father was interviewed to work on the Manhattan Project, he was a chemist, electrical engineer and computer systems manager.

Julius Shapiro in Chromatic Lab. in Paramount Building New York, Late 1950’s Courtesy Laurie Shapiro

He worked with Nobel prize winners and loves to play chess. He’s 93 now and doesn’t like to talk much about the past. He remembers his work at Chromatic as a project engineer working with the tubes.

Julius Shapiro in Chromatic Lab. Paramount Building Late 1950's Courtesy Laurie Shapiro

Julius Shapiro in Chromatic Lab. Paramount Building Late 1950’s Courtesy Laurie Shapiro

Laurie invited me to call her father and so I did.

It was a very pleasant conversation and Mr. Shapiro asked me to call his good friend Seymour Yusem and co-project engineer at Chromatic. “Sy would know everything I wanted to know” and so I did. Thank you sir.

I called Mr. Yusem, and left a voice message on his machine. He returned my call several hours later. It was a most interesting conversation and learned that Sy is 88 years old and started work with Chromatic from 1957 to 1962. He was a project engineer working on the Chromatron color tube receiver. He co-authored a technical paper with Robert Dressler entitled “THE PDF CHROMATRON-A SINGLE OR MULTI-GUN TRI-COLOR CATHODE-RAY TUBE” it can be found in the Proceedings of the I.R.E. Vol. 41, No. 7, July, 1953. Robert Dressler “was the brains of the project” and headed up Sy’s unit and has since passed away. Mr. Yusem sent me a copy and two other technical papers, thank you very much sir. (Laurie told me that Sy went to Japan to meet Sony, but he did not mention this in a follow-up email).

Mr. Yusem told me that the problem with the Chromatron was its resolution. It had very high brightness, but low resolution (not enough phosphor stripes across the screen) He said the RCA system had high resolution, but low brightness. He said RCA could have increased the brightness by enlarging the holes in the shadow mask at the expense of lowering the resolution.

Mr. Yusem explained the Telmeter pay TV system Paramount was working on in conjunction with a coin operated set top box. By inference, I make an assumption that the Chromatron was a part of this system because of earlier research on the subject.

Laurie’s father said Sony purchased the license and development rights to the Chromatron for one million dollars at a restaurant and Mr. Yusem said “When I was told that Sony had purchased the patents and development rights it was also stated that Sony had plans to transistorize the chassis. I took that to mean there was no future for me with Sony”.

Mr. Shapiro left Autometric a year earlier then Mr. Yusem and accepted a position as a Computer Systems Manager with another company.

Mr. Yusem left Autometric formerly Chromatic in 1962 and joined the CBS Television Network as a project engineer. He said they had a color TV plant. He received his BSE from City College.

Finally, Mr. Yusem sent me a black and white glossy 8×10 photo, an original of a prototype chassis built by Autometric in 1962 to demonstrate the Chromatron to various manufactures. The arrow points to the encoding section which could be changed for different encodings required for 1 gun or 3 gun Chromatrons. Mr. Yusem said Sony transistorized the chassis, which he felt was an achievement for that time. Thank you very much for this piece of history sir.

I feel honored to have spoken to these pioneering electrical engineers from the early days of development work on the Chromatron and to share their stories. We barely scratched the surface and would like to learn more. We will update you further.

Thank you Laurie for making it happen.

Update August 11, 2014: We took a pleasure trip to NYC with the intention of interviewing Mr. Shapiro and Mr. Yusem, but unfortunately unforeseen circumstances prevented our meeting.

Below, see the 1962 Chromatron prototype chassis.

1962 Chromatic prototype Chromatron Tube Chassis

1962 Chromatic prototype Chromatron Tube Chassis Courtesy Seymour Yusem

Update, January 26, 2020

With sadness, I just learned of the passing of Mr. Shapiro January 13, 2020. From his daughter’s Facebook posting, “My wonderful and brilliant and hilarious and very very curmudgeonly 99-year-old father Julius (Julie) passed away peacefully tonight with no pain we could detect. I will always be grateful I was there for his last breath. His last words to me two days ago were, “I love you.” Laurie Gwen Shapiro. More at her Facebook page.



The Lawrence Chromatron by Chromatic switches to an inline three gun.



Chromatic fights back.




Going back to the story, in March, 1961, Sony saw the Chromatron demonstrated at the Autometric booth within the IRE trade show in New York. It was used by the military to help identify friend or foe. What Sony immediately knew was this very bright tube is what they were searching for as an alternative to the RCA shadow mask color system. Akio Morita, Sony’s co-founder, attended the show with his young engineers and immediately called the President of Autometric to arrange a meeting. The next day it was done as Julius Shapiro said, “the deal was cooked up after an executive has one drink with a Sony man for a million dollars”. Sony had just purchased the patent and development rights to market the Chromatron in the United States and the rest of the world.

For Julius and Sy, this meant the end of their careers at Autometric, but by no means the end of their contributions in their respective fields of endeavor.

For Sony, this was the start of a new beginning. They knew it would be a difficult task but accepted the challenge. According to an article appearing in the German magazine, Der Spiegel, dated September 23, 1964, Sony assigned 50 members from the Research Institute to work on the completion of the Chromatron. History books tell us that Sony failed in their efforts to develop the Chromatron, but they did not fail. Their continuing work on the Chromatron ultimately led to an improved Chromatron renamed Trinitron. They corrected the Lawrence tube problems with their own ideas and Trinitron went on to be the most successful color television system in the world with a 40 year production run. Julius Shapiro and Seymour Yusem, two dedicated project engineers can be very proud of their early contributions to the project.

The (Autometric/Sony) Chromatron (Sony started development in 1961 under Paramount license) CRT has now evolved into an inline three gun CRT offering in excess of 300 foot-lamberts highlight brightness in normal operation. (A typical shadow mask CRT develops 30 to 45 foot-lamberts highlight brightness.) A slender black stripe is laid down between each color phosphor to increase contrast. The tube does away with the beam switching grid with it’s associated r.f.power which characterized the older tube. The post-deflection focusing second-anode grid is an array of closely spaced parallel taut wires located about 1/2 inch in front of the phosphors. The grid is operated with about 6 KV difference between it and the electron guns. Source: Electronics World, January, 1964.

The story continues below in my various collections and concluding with the finding of an extremely rare working Sony Chromatron in 2013.

There was another color system developed to improve upon the RCA system. Please see the Indextron page.




September 8, 1964

Sony Prototype 19 inch One Gun Chromatron

A prototype 19 inch one gun Chromatron was put into pilot production and shown for the first time at Sony corporate headquarters in Japan on September 8, 1964. There are conflicting reports that this set was a 17 inch, but the evidence presented here, indicates it was more likely a 19 inch color set. Here, a photo of the prototype 19 inch Chromatron.

Courtesy Sony History

Courtesy Sony History

Notice that it is a horizontal designed console. The first production model had a vertical console.

This image below, is believed to be the only known photo of the Sony prototype 19 inch one gun Chromatron CRT. The size conflict may have arisen because the envelope of the tube is 19 inches, but the actual diagonal viewable measurement is just over 17 inches. Sony claims a peak brightness level of 90 foot-lamberts white or about 2 1/2 times greater then the shadow mask type. The three gun version offers more then 300 foot-lamberts peak white.

Sony struggled with the manufacturing process of this set as discussed below and the one gun 19 inch Chromatron never made it to final production. The one gun with its complicated switching grids was abandoned in favor of a three gun version and the first production model Chromatron with three guns went on sale in Japan only in May, 1965.

Continuing research, in December, 1966, Sony completed a prototype 7 inch Chromatron using the just invented, right out of the lab, one gun with three inline cathodes combined with the Chromatron CRT with its wire selection grid. Now, the Chromatron was even brighter using three inline cathodes within a one gun structure, a remarkable achievement! This prototype set later made its way to final production and was introduced in the United States in April, 1968 as the model KV 7010U.

This new form of television CRT called the Chromatron was later abandoned in just three short months and a brand new 7 inch tube was substituted in the same but modified chassis and designated the KV 7010UA, christened “Trinitron”. The exteriors of the two models look identical. The Trinitron eliminated the wire grids, instead using the newly invented “Aperture Grill” which was more like the traditional shadow mask, but instead used unbroken vertical slits which allowed much more light to pass compared to the shadow mask. The Arpeture Grill was less efficient, but said to be 2 1/2 times brighter then the existing shadow mask set of the day. No doubt this was done to lower manufacturing costs and it was a device that Sony could patent and call their own.


Sony anounced the invention of the Trinitron in Japan on April 15, 1968 when they unveiled the 12 inch model KV 1310 with production availability mid October, 1968 in Japan (which is the same set as the domestic KV 1210U) but it appears that the first Trinitron, being the 7 inch model KV 7010UA went on sale in the United States prior to October, 1968. The following material below, describes in detail how all this came about.


Article about the upcoming Sony Chromatron color television in December, 1964 issue of Radio-TV Experimenters magazine. View the PDF.

Courtesy Radio-TV Experimenter magazine

Courtesy Radio-TV Experimenter magazine


1965 Sony Chromatron 19C 70 Color Television

Update July 24, 2020: The “Chromatron Corner”, within the original Sony building in Tokyo which was demolished in 2017 and replaced with the Ginza Sony Park development. This ultra rare photo from 1965, exhibits five working 19C 70 color televisions using Sony’s newly developed Chromatron tube’s and the latest video recording equipment. The walls displayed Sony magazine advertising from the US. No color on the screens? Apparently limited color programming in Tokyo 1965. (The US went prime time color programming during the 1966-67 season.) Photo source unknown, credit Visions4 Magazine.



You are looking at the world’s first mass produced Chromatron color television. What’s so special about the Chromatron you ask? Dr. Ernest O. Lawrence invented the tube in 1951. It was a single gun CRT using vertical stripes of red, green and blue on the screen much like the Sony Trinitron, now out of production due to the emergence of flat panel displays. The design patent by Dr. Lawrence, a Nobel prize winner from California, came 17 years prior to the Trinitron! Additionally it did not require a shadow mask, thereby allowing for a 75% brighter image. Behind these stripes were vertical wires which could be charged with electric current to deflect the single electron beam to each of the stripes. The tube did not require convergence circuitry, used less parts and lower power consumption. The bright color images of the prototypes looked promising, but unfortunately, Paramount Pictures, Chromatic Television Laboratories, a subsidiary of Paramount, Litton Industries, licensed under Chromatic and others failed to solve the difficult manufacturing process and a mass produced Chromatron was never brought to market until this Sony 19C 70 in Japan in 1965. A rare photo, believed to be one of a very few existing photographs of a 19 inch 1965 model 19C 70 Chromatron by Sony on display at the Sony History Museum. This model was first shown in Japan in September, 1964 as a prototype using one gun. In May, 1965 the 19C 70 Chromatron went on sale to the Japanese market only, using a delta three gun system. The chassis was not transistorized. Sony offered a unique life time warranty on it’s first color television product, if it broke, Sony fixed it for free. Only 13 to 18 thousand units were sold in 1965 and 1966 at a very expensive $550.00 American dollars, but it cost Sony more then double that amount to produce each one. The Chromatron was a unique color CRT which promised very bright images and had many technical advantages over the conventional shadow mask color CRT. It was the first Chromatron to be sold to the public, but Sony was plagued with numerous technical problems, only 2 or 3 out of 1000 on the production line were good, so Sony stopped production * in September, 1966.
Update April 24, 2015: To clarify, we now believe the production problems were not with this set, the 19C-70 delta three gun Chromatron, but rather with the pilot production one gun Chromatron which we believe never went into final production. The Delta three gun Chromatron sets, 19C-70, 80, 90 and 100 were a compromise until the Trinitron was perfected and ready for production. The Chromatron development did not die, you can read more about the Chromatron below and on the internet.


The Sony 19C-70 Chromatron is currently on display in the Sony Ginza building in Tokyo during the exhibition “It’s a Sony” running from November 12, 2016 through March 31, 2017. Below a photo while on display at the exhibition, courtesy the Sony Corporation.




Sony Chromatron 19C 70 courtesy Sony Archive History Museum

Sony Chromatron 19C 70 courtesy Sony Archive History Museum


We just found this rare 1966 publication. It’s a Sony tourist handout souvenir booklet containing 43 pages of information about Sony’s history past and present. Richly illustrated in color on high quality, thick paper stock. What we especially appreciate is the Chromatron feature. We visited this same 5th Avenue Sony showroom as shown in the book, in September, 1968 and there, for the first time, saw the Sony KV 7010UA and KV 1210U Trinitron televisions which were just being introduced to the public. They were not for sale in the showroom, but they were taking orders. Below, a small portion of the publication. Tap on any image to see an enlargement.

* Update, July 21, 2014: Just found out from my online friend, Noriyoshi from Japan, that Sony manufactured two additional Chromatron models in 1967. They are the 19C 80 and 19C 100 both delta three gun, all tube televisions. Noriyoshi is currently repairing a 19C 100. More information to follow.

* Update August 26, 2014: My friend Jerome Halphen found this Chromatron data book which has detailed information on the Sony Chromatron 19C 70. Unfortunately it is not written in the English language. Perhaps one of my Japanese viewers could translate the following 8 pages. Thank you for the scans Jerome. The book discloses yet another Sony Chromatron model previously unknown by this author, the model 19C 90. We now have a total of four Sony Chromatron models the 19C 70, 19C 80, 19C 90 and 19C 100. The last three were manufactured in 1967. View the PDF.

Chromatron repair book 1 525 WP





Yaou Chromatron Color Portable

I found this photo with caption below, in the August, 1965 issue of Popular Mechanics magazine. It is also referenced in the website and in the book, The History of Television, 1942 to 2000 by Albert Abramson. This book recites that Yaou Electric Co. of Japan produced a line sequential Chromatron with an 8 inch CRT and introduced it to the Japanese market as early as 1963. If this is true, this set could claim the title as first Chromatron to be marketed, ahead of the above Sony 19 inch Chromatron in 1965. The Popular Mechanics article states this television had a planned U.S. introduction in Fall, 1965. This photo appears to show only a VHF tuning selector, however it may have an integrated UHF tuner. If the set was marketed in 1965, the FCC required that all televisions sold after 1964, incorporate a built in UHF tuner.


Update October 11, 2013

My friend Jerome Halphen from Paris, France and his friend Noriyoshi recently visited the NHK museum in Tokyo, Japan. There, they found on display, the Yaou Chromatron Color Portable TV among other things. This model is called GENERAL TELEVISION COLORNET GTC-9.

Jerome and Noriyoshi October 10, 2013 courtesy Jerome Halphin

Jerome and Noroyshi October 10, 2013 courtesy Jerome Halphin

Report from Jerome H.

“What we previously called the YAOU TV is in fact a GENERAL (TELEVISION COLORNET GTC-9.

Noryoshi said that he had one to repair 10 years ago and that it had a very mediocre (course) color picture. This proves that at least some where indeed sold on the Japanese domestic market.

Noryoshi also estimated the NHK date label as wrong, he said 1965-1966 which would be consistent with the YAOU text we have on the B&W only photo we had previously. Maybe 1963 was the prototype date issue and that’s why NHK labelled it so.

Another thing Noryoshi told me is that the * entire YAOU development team was poached by SONY who was then midstream between the non-working Chromatron and the not yet developed Trinitron. This would make sense as SONY surely needed to muscle its teams in color CRT technology when they were frantically trying to come up with a viable color CRT solution.

Speculation here, but if YAOU’s R&D became a hollow shell, they probably dropped the project, sold the technology to GENERAL who ultimately marketed the TV.

The schematic is very advanced for a 1965 color set. It’s entirely transistorized except for the usual 3x miniaturized EHT rectifiers. The tubes are IDK-37 or 1DK-37, probably the same as in the SONY 5″ B&W 5-303W.

It’s a cute set! i asked Noryoshi to grab one if ever he sees another. The color CRT has no reference other than COLORNETRON. It uses 14.4KV final EHT voltage and a 4.7KV to 6.3KV swinging voltage on the color selection grids.
Y Luminance is applied to the Cathode, the Color signal to the G1 Grid.”

Update December 12, 2014:

* We insert here a translation from a Japanese blog, AV and Home Theater.

“1964 /? HachiO Electric Co., Ltd. is the world’s first 9 form line sequential method All transistor color TV launched the “color net” GTC-9

Adopt a “color net” Kobe Kogyo (now Fujitsu Ten) and joint research and development the single electron gun color picture tube “color magnetron”

1965 /? Sony pulled out all the human color magnetron development department of Kobe industrial”

A few photos courtesy Jerome Halphen.

General Colornet GTC-9 courtesy Jerome Halphin

General Colornet GTC-9 courtesy Jerome Halphin

General Colornet GTC-9 courtesy Jerome Halphin

General Colornet GTC-9 courtesy Jerome Halphin

Thank you my friend Jerome and to Noriyoshi. Jerome is a long time collector of vintage television and Noriyoshi is an electrical engineer in Japan, he has his own website:

To sum up, I’m still conflicted on the introduction date, so for now, will keep this television in place. (1965) We now know it went to market in Japan therefore, all references on this site to the Sony Chromatron 19C 70 being the “first or only” Chromatron to be marketed to the public are amended. A very interesting addition to Chromatron Color CRT history.

Update October 16, 2013:

Additional research courtesy the Radio Museum revealed the following,

Yaou Radio Co ltd ; Kanagawa-ken
Yaou Electric Co., Ltd.

Yaou Electric Co.Ltd. was a manufacturer of radios and tv-sets, marked as “General” on the front.
Yaou is mentioned in “The history of television, 1942 to 2000″ by Albert Abramson : They introduced their first color-TV in spring 1963 with a line-sequential 8” Chromatron one-gun type CRT.
It may be hard to identify “General” as “Yaou” products because the circuit diagrams inside of their radio models are issued (sometimes) in Japanese language.
Yaou Electric Co. Limited. 1116 – Suenaga Kawasaki-Shi Kanagawa-Ken Japan

I found the Patent: Application January 25, 1963 Patented February 7, 1967 Number 3,303,275. With this information, you can research the Patent on-line.

Update April 6, 2014:

I found a July, 1965 IEEE paper stating that the Yaou Colornet utilizes a variation of the Lawrence tube and was available late 1965.
Broadcast and Television Receivers, IEEE Transactions on (Volume:11 , Issue: 2 )
Date of Publication:
July 1965
38 – 49
Digital Object Identifier :
Date of Current Version :
12 November 2007
Issue Date :
July 1965

This confirms Noriyoshi’s belief that a 1963 release of the Yaou Colornet was incorrect.

Update, May 31, 2014. Additional details appear.

In the November, 1964 issue of Electronics World, we found the article posted below. The CRT is called “Colornetron” and is 9 inches? The new tube and circuitry is still going through the patent process and details are not available. It is revealed that this CRT uses line-sequential color generation. In this approach, the color phosphors are laid down in fine horizontal lines down the screen, unlike the Sony Chromatron.

Look at the left photo. There are small differences in the design compared to the model displayed in the NHK Museum. The handle is now a leather strap instead of a rigid folding handle. The two control knobs on the side appear to be mounted higher and the speaker grill is mounted lower. There appears to be additional “filler” material surrounding the Colornetron CRT compared to the 9 inch black and white model on the right, therefore we think this article misstated the screen size and the Colornetron CRT is 7 1/2 inches as reported above. This set still does not appear to have a UHF selector dial which was required after 1964.

Yaou General Colornet GTC-9 Colornetron

Yaou General Colornet GTC-9 Colornetron

Look at the next photo below. This is the 1965 Philco-Ford model N1052BK 9 inch black and white television that was sold by Ford dealerships as an accessory for the Ford Mustang. A dead ringer right down to the rocker switch and identity tag. The only difference is that this Philco model added the required UHF tuner. You can see the UHF selector on the left side of the control panel. Did Philco secure a license from Yaou Electric to market the Colornet under the Philco-Ford brand name? We do know that Philco worked for 10 years in the 1950’s to develop the beam index tube. The project was terminated without success. We recently learned that Philco was still interested in alternate color picture tube technology when in 1967, they purchased a license from Paramount Pictures Corporation to develop a Chromatron color television set. More about this further down in this article. To the best of my knowledge, the Colornet was never marketed in the United States but the remarkable resemblance to the Yaou black and white model tells me Philco may have been working on the Colornet.

Philco 9 inch clone of Yaou Eelectric 9 inch black and white

Philco 9 inch clone of Yaou Eelectric 9 inch black and white courtesy Amptech Systems & TUBETVSHOP.COM

Update February 28, 2015

An “Outline of Engineering Design of the COLORNET System 9 Type Color TV Receiver” by Yasumasa Sugihara, Hisao Ito and Akira Horaguchi (Yaou Electric Co. Ltd., Kawasaki. Courtesy Yaou Electric Co. Ltd. View this PDF Said to have 80% beam efficiency with 250 horizontal lines of resolution. 30 watts AC, 20 watts DC. Written in the Japanese language, your browser may ask you to download a foreign language plug in. Copy and paste the text into the Google translate app for translation.

English translation by Google Translate. Refer to PDF for circuit diagrams, photos.

We developed a single-electron gun color picture tube with a color switching grid, a color-emission tube, and commercialized a new color-emission system that uses a line-sequential coloration system for the color reproduction method.  All circuits are transformed into transistors and

 -This is summarized as a tabular color television, and its operation principle, design outline of each circuit, structure and features are introduced here.
 1. Preface
 (3) Although the receiver using the electron gun shadow mask has a lot of outstanding performance, the screen is a little dark, and it is difficult to handle.  Due to their high price, efforts have been made in each country to search for the best alternative.
 Most of the carater revs that have been on the market so far have used shadow mask type picture tubes.
 Although the manufacturer’s circuits were the same or different, this machine was summarized from the basic new way of thinking described below, and it has been conventional.
 Introduction of the author Masaru Sugihara
 Yasumasa Sugihara 1945, graduated from the Department of Electrical Engineering, Tabijun University of Technology
 It can be said that it is a new product that is fundamentally different from that of.
 (1) A single-electron gun picture tube 9-type current collector was used.
 (2) A color-based system that uses a line-sequential method for color reproduction.
 I used
 Akira 25 years, engaged in eight design, Akira
 Joined Europe Electric Co., Ltd. and worked for FM communication in Japan for 27 years, devoted himself to trial design of TV receiver
 Shi, Color TV, To
 Currently General Manager of 2nd Technology Department. Regular member.
 Itoh Hisao
 Tomio Ito Graduated from the Department of Electrical Engineering, Faculty of Engineering, Keio University in 1958.In the same year, joined Europe Europe Electric Co., Ltd.  He is in charge of the development of the TV, and is currently the general manager of the Engineering Section 1 of the 2nd Engineering Department.
 Look at Akira
 Yu Douguchi Graduated from Tohoku University, Faculty of Engineering, Department of Communication Engineering in 1958.  In the same year, joined Hachiyo Denki Co., Ltd., engaged in the design business of measuring instruments, engaged in the development of color TVs since 1956, and is currently the second section chief of the first technology division of the second technology department.
 “An Outline of Engineering Design of the COLORNET System 9 Type Color TV Receiver” by Yasumasa Sugihara, Hisao Ito and Akira Horaguchi (Yaou ElectricCo. Ltd., Kawasaki)
4) Compact and lightweight as a portable color television. Photo 1 shows the external appearance of this unit, and Photo 2 is received by this unit.
 It is a black and white image.
 2. Color Netron
 COLOR NETRON is a product name of a single electron gun picture tube that is a so-called “Lawrence tube”.
 It was developed in collaboration with Todo Kogyo Co., Ltd. Figure 1 illustrates the array of electrodes on the front surface of the phosphor.
 In addition to the color switching grating, a focusing grating is provided immediately before it, which has a great effect on improving the focusing of the electron beam.
 The feature of the CRT is that it has an electron beam transmittance of 80% or more, which is about 5 times that of a shadow mask type CRT, and is extremely bright.
 Another major feature is the post-stage acceleration and post-stage focusing, so the main deflection power is very small and the
 The conditions for forming a distort are satisfied.
 If the brightness of the screen is roughly proportional to the electron energy applied to the fluorescent surface, it will be added to the fluorescent body.
 It is proportional to the product of the voltage and the beam current reaching the phosphor: the high voltage of the single electron gun picture tube is Epc, the cathode current is Ikc,
 Figure 2
 Color netron cathode current vs. luminance characteristics
 Letting ηe be the current transmittance, it is given by the following equation.
 The electric power Pc that reaches the luminous body is (1)
 Its area is about 1/4 of that of a shadow mask picture tube.
 Therefore, the brightness is four times larger, and therefore the unit area
 By comparison, when the high pressures are the same, the brightness is eight times as high, but in reality the high pressure is low because the picture tube is small.
 The beam current is also a single electron in the shadow mask picture tube.
 Since you can’t get as many as a gun
 The gain of the Netron is 3 to 4 times as bright as that of the 16-type shadow-mask picture tube.
 FIG. 4 is a diagram showing the relationship between Ron’s cathode current and brightness.
 3. Color Net System
 There are three methods of reproducing a color image with a single electron gun picture tube, a surface sequential method, a line sequential method, and a dot sequential method, but these three methods are examined in detail.  As a result, we found many features of the line-sequential system and were confident that it could be put to practical use in the case of a small receiver.  It is
 (1) Since the color switching is performed within the horizontal blanking period, whether the beam current utilization ratio should be compared with the dot-sequential method.
 It is excellent.
 (2) Is the color switching frequency 1/3 of the horizontal scanning frequency?
 The power required for switching is reduced to less than 1/10 compared to the point-sequential system that switches at 3.58 Mc.
 The circuit was made into a transistor.
 (3) The color switching frequency is low and the power consumption is low.
 The high pressure of the shadow mask picture tube is
 Cathode current
 Is 11es, the current transmittance is ηs, and the power reaching the phosphor is Ps.
 Now, if the transmittance of the shadow mask is 16% and the transmittance of the single tube is 80%, then ηc/ηs in Eq. (3) is 5.
 In addition, taking into account the three-distribution ratio of the shadow mask type CRT, Ikc/Iks is set to 1/2.5.
 Assuming the current of the child gun,
 (3) is
 It looks like this:
 Figure 1
 Electrode array in front of phosphor in color netron
 (4) This equation is used when the beam current is effectively used during the scanning period, and is limited to the linear-sequential equation or the surface-sequential equation in the case of a single electron gun picture tube.  In the case of, the electron beam is limited by the blooming characteristics, and the relationship of Eq. (4) is
 The number is 2 or less.
 Volume 19 Issue 4
 (271) 29
 Electron gun image
 Color net system 9 type
 Color receiver 〓 Paper
 Tron type 9
 20 mmφ, effective screen is 157 mm × 115 mm, and 16-type
 90° deflection using a valve, neck diameter
As a result, unnecessary radiation is extremely low.
 (4) Large switching power may be injected into the picture tube.
 Since it has disappeared, it is advantageous in the manufacturing technology of the picture tube.
 (5) The circuit configuration is very simple and the switching frequency is low.
 Therefore, the operation is very stable.
 (6) The color fidelity is better than that of the dot-order equation. The only drawback of this method is that the white color is reproduced.
 Since one scan line is required, the number of equivalent scan lines is 1/3, but it is practical when the screen is small.
 The phosphor of the picture tube was applied in the form of thin filaments in the longitudinal direction so as not to be affected by the earth’s magnetism.
 Since it is scanned in the horizontal direction, the intersections of the warp threads and the weft threads of the three colors also emit light, and fine net-like color reproduction is performed.
 From now on, I decided to call it the color-net system.
 Currently, a staircase wave is generated by a storage counter, and color switching is easily performed by a switching circuit using transistors.At the same time, only one demodulator is used for line-sequential demodulation for color signal demodulation.  We devised a method to obtain the color difference signal, which saved about 10 transistors and dozens of circuit components, and the single balancer because of one demodulator.  Being an electron gun
 Together, they can be completely stabilized, causing imbalance of each color difference signal due to changes over time.
 The chromaticity signal of the NTSC signal depends on the I and Q signals.
 Since the subcarrier of 3.58Mc was double-balanced modulated in order to demodulate this, as shown in Fig. 4, it has the same frequency as the subcarrier and the same phase as the desired detection axis.  The reference subcarrier wave must be inserted; the color switching time is sufficiently long for one cycle of the subcarrier wave as in the case of the line-sequential type.
 In some cases, the line sequence with the three-color detection axes is
 By adding the next reference subcarrier, it is possible to obtain a line-order-order color signal with only one demodulator as the output.
 In this instrument, we used a symmetric shape with the detection axis shifted by 120°. In addition, the frequency of the crystal oscillator was 3.58 Mc, which was only 1/3 above or below the horizontal scanning frequency.  Let fSC be the subcarrier frequency, fH be the horizontal scanning frequency, and fR be the frequency of the water crystal oscillator.
 Figure 3 did.
 The chromaticity signal system is mainly shown in the system diagram of this machine.
 4. Offset subcarrier demodulation method
 It takes 3H from the time when the phase matches the same time until the phase becomes the same again, that is, fR is relative to fSC.
 The 360° phase advances, and Figure 5 illustrates this.
 In the figure, OP shows the phase of the standard 3.58 Mc, and OQ
 In embodying a color net system, a line-order-order color switching circuit and a method for obtaining a line-order-order color difference signal are new methods that have not been used until now.  It took a lot of work and struggles to reach the circuit used in the machine, that is, the gate pulse by the ring counter was initially used.  Start from a rudimentary method of generating and sequentially gated three demodulators to obtain a sequential color difference signal.
 However, it required many circuit parts, the operation was complicated, and there was a problem in terms of cost.
 Figure 4 Recovery
 30 (272)
 For convenience of explanation, one period of horizontal scanning is set to H at fSC+1/3fH.
 explain about.
 To show that, fR and fSC are
 Is OP
 In contrast, it shows that the phase is continuously advanced.
Figure 5 Reference subcarrier phase explanation diagram
 Therefore, a sawtooth wave with a period H is measured with an appropriate amplitude and polarity.
 If the output of the crystal oscillator is phase-modulated, from 0 in Fig. 5 to abcd
 The phase shifts stepwise by 120° for each H period as shown in Fig. 4 to obtain a line-sequential symmetric detection axis.
 Since fR is offset by only 1/3fH with respect to fSC, it is called the offset subcarrier modulation method.
 Since there is a phase relationship as described above between fR and fSC, the color burst added to the phase detection circuit of the APC circuit is
 Therefore, the gate pulse to be added to the burst amplifier is taken out by the storage counter or the color switching circuit.
 Pulse with a period of.
 5. Outline of each circuit
 Although transistorization of black-and-white receivers is progressing rapidly, in the case of shadow mask type receivers, there is a large deviation.
 It is considered that the device is still in the research stage because of the power consumption, and because of the technical difficulty that is required from the viewpoint of performance, this device is difficult to make into a transistor.  It is a solution of the problem and converted to a full-transistor.
 Many innovations have been made in the system and color switching circuit.
 Figure 6 Intermediate frequency characteristics
 2 Connect the bi-filtrator to the input circuit of the image detector.
 The variable resistor is adjusted so that the attenuation is maximized. A key AGC is used as the AGC, which has an AGC characteristic of 50 dB or more.
 In the case of a color receiver, the differential phase and
 The gain is a particular problem, with the overload characteristics for the tuner and the first and second stages of the intermediate frequency amplification, and the large amplitude for the final intermediate frequency amplifier and the second image detector.  Non-linear by
 It is necessary to pay particular attention to 5.2.
 4.5Mc voice intermediate frequency signal is the final stage of intermediate frequency amplification.
 There is no difference from the black-and-white TV except that it was extracted, but in order to obtain sufficient profit, the voice intermediate frequency amplification stage is
 Since the voice output is a small portable television, the distortion-free output was set to 200 mW.
 5.3 Synchronous deflection circuit
 The sync separation circuit, synchronous amplifier circuit, AFC circuit, horizontal/vertical oscillation circuit are omitted because they are similar to the black and white transistor television.
 Since the 9-inch color netron has a deflection angle of 90° and a neck diameter of 20 mmφ, the deflection yoke used for the black-and-white transistor television can be used as it is, and it can be accelerated at the latter stage.  What
 The acceleration voltage applied to the phosphor is 14 kV, but the focusing grid voltage that dominates the main deflection circuit is only 6 kV.  In addition, the horizontal deflection electric power of about 16 W is consumed by about 16 W in the 16-type window mask type receiver, while it is about 1/about 14 W.  Not less than 5, the phosphor voltage, focusing grid voltage, and color-switching grid voltage change comparatively.
 5.1 The NTSC tuner has the same white
 No. receiving system
 The one used for the black television and the one with an improvement in the essential performance are used.
 In other words, the standard for black-and-white TVs is restricted in terms of frequency characteristics in the pass band and drift of the oscillation frequency, and it is self-contained as a portable television.  The total sensitivity of the set is less than 10 μV and the tuner noise figure is 6 to 8 dB in order to enable wide-range practical use with the antenna.
 The intermediate frequency amplification section consists of 4 stages of 2SA239×2 and 2SA240×2.
 In the amplification circuit, near the depth of the voice trap and the subcarrier frequency.
 Special attention must be paid to the characteristics of
 Figure 6 shows that this 3.58 Mc
 It is very difficult to increase the attenuation of the voice trap by reducing the nearby attenuation with the passband characteristics of the standard IF circuit of the device.
Figure 7 High voltage generation circuit
 In other words, there is almost no color shift due to mislanding, and since the average beam current is used at 150 μA or less, the automatic control circuit for high pressure is used.  There is no need to install a circuit, and the circuit and structure have become very simple.
 Figure 7 shows a high-voltage generation circuit, in which a voltage is applied to the color switching grid by a voltage division method, which is variable for fine adjustment of color purity.  Used on the yoko and this machine
 This is a comparison of the magnitude with the biased york. 5.4 Video amplification circuit
 The video amplifier circuit has three stages because of the inclusion of the delay circuit, but both the first stage and the second stage are emitter followers.
 The second image detection output is approximately 2Vp-p, and the cutoff voltage of the picture tube is designed to be 60V at maximum.
 The gain of the image amplification circuit needs to be 30 dB, but with this unit, a maximum gain of about 38 dB can be obtained using the 2SC-70.
 The frequency characteristics are shown in Fig. 8, but it is possible to obtain sufficient resolution with a small picture tube.
 The sync signal, video signal for key AGC, and chromaticity signal are all taken from the emitter of the first-stage video amplifier.
 5.5 Bandwidth increase circuit
 The required gain and passband characteristics are obtained with a two-stage bandpass amplifier.
 The required selectivity and bandwidth are mainly obtained by the collector circuit of the first stage bandwidth amplifier, and Figure 9 shows the different characteristics of each stage.
 Figure 9
 Band amplifier characteristics of each stage
 It shows the sex.
 Antenna input terminal to demodulator
 Figure 10 Chromaticity signal system overall characteristics
 Figure 10 shows the total passband characteristics at -3dB
 The width is designed to be at least ±500kc or more.
 5.6 color synchronous amplifier circuit
 The burst signal is extracted with a 3H period gate pulse.
 Photograph 4 is the waveform of the gate pulse and Photograph 5 is gated.
 This is the output waveform of the burst.
 This is done by changing the equivalent tuning capacity on the input side.5.7 APC circuit
 32 (274)
This machine uses a 3-interval APC circuit, and is
 Fig. 13 If the gates that came from the phase-shift circuit are gated every 3H, the
 Since the control voltage is reduced to 1/3, the detection sensitivity of the phase detection circuit and the control sensitivity of the crystal oscillator are increased.
 Figure 11 shows the control sensitivity of the crystal oscillator circuit, using the Varicap 1S48 as the reactance element.
 12 shows an APC circuit and a crystal oscillator circuit.
 5.8 Phase modulator
 In order to create a line-sequential reference subcarrier,
 As described above, the output can be phase-modulated with a sawtooth wave of period H.
 It is a vector diagram of the standard sub-carrier waves with intervals, and the deviation within the H period of the phase modulation can be kept within ±5°.
 In principle, phase modulation uses a phase shift circuit as shown in Fig. 13, and
 Volume 19 No. 4 using varicap to automatically generate phase displacement
 Fig. 14 Phase modulation circuit
 A sawtooth wave was added to this, and the actual circuit was as shown in Fig. 14. In Fig. 13, the power supply impedance of the coil was set.
 Color Net System Type 9 Color Receiver 〓 Paper
 Figure 12 Phase detection circuit and water crystal oscillation circuit
 Assuming that is negligible, when the pressure is induced,
 On both ends of the cable as shown
 This formula is for C, R
 The value of C, R
 (275) 33
 Depending on the selection method, θ is from 0° to approximately 180°C.
Resistor Unless otherwise specified, 1/8V type, 1/3 is 1/3 winding type, 1/10 is 1/10LPS
 ● The resistance of all CR compound parts is ±10% at 1/10W ●Battery ● △…0.01μF High permittivity porcelain capacitor
 ● 220P~4,700P is Polystyrene capacitor
 50V without voltage input.0.001-0.22 is Mylar film capacitor.
 (±20% unless otherwise specified) 50V without voltage
 ● MP… Metallized Paper Capacitor ● MM… Metallized Mylar Capacitor 1P~150P are temperature compensating porcelain capacitors
 (SL characteristics are specified unless otherwise specified)
 ● (AS)
 ●(LG) is lug type, (HF) is for high frequency ●1~4,000 is electrolytic capacitor.  (Capacity [μF]/Withstand voltage [V])
 Color net system 9 type
 Color receiver 〓 Paper
 ,(AR) is a solid aluminum electrolytic capacitor
 , (L) is for low temperature, (T) is tube
Regardless of
 From the fact that (8) is established, it is theoretically shown that the amplitude of the output e0 does not change due to changes in C and R, which is convenient, and this offset subcarrier method is convenient.  For 120° phase modulation
 5.9 Demodulation circuit
 The demodulator may consist of a single transistor, and if a base-type reference subcarrier of the line type is added to the base and a chromaticity signal is added to the emitter for demodulation, line-sequential correction is performed on the collector side.  It is possible to obtain a color difference signal.
 Attenuates 3.58 Mc and its harmonics.
 In order to widen the voltage to a level sufficient to excite the grid, a single color signal amplifier is provided. The frequency characteristic is about 400 kc at -3 dB. Photograph 7 shows the color signal.  This is the output waveform of.
 A horizontal blanking signal is input to the collector of the demodulator. 5.10 Color switching circuit
 The voltage applied to the color switching grid is the 3rd floor staircase with a period of 3H.
 Such a staircase wave is generated by combining the accumulation counting circuit as shown in Fig. 15 and the frequency divider of 1/3 of the horizontal scanning frequency.  A clinching oscillator was used, Photo 8 showed the color switching voltage waveform.
 The color switching output stage is a switching circuit, and the output voltage is approximately
 Photo 9
 36 (278)
 Photo 7
 Figure 15 Accumulation counter circuit
 Output waveform of color signal
 Since the single-electron gun picture tube is used, it is no longer necessary to use the convergence york or the convergence board, which is also very useful for downsizing.  However, it was very unlikely that the effect of geomagnetism would be affected by simply using a simple magnetic shield, and we promoted the portable use of caratelebi.
 The electrical circuit consists of four printed boards, connected by connectors for convenient after-service.
 Photo 9 shows the appearance of a chassis.
 The cabinet is molded by plastics, and the
 A filter with a transmittance of 80% is used on the front side to prevent the interference of external light.It can be used not only with an AC power source but also with a DC power source.
 It is designed to be used in many ways.
 7. Conclusion
 The color netto 9 that was put into practical use this time is of great significance in that the line-sequential method was put to practical use, in addition to the fact that a single electron gun picture tube was used.
 Photo 8 Color switching voltage waveform
 At 300Vp-p
 Appearance of chassis
 The force circuit is stepped with a transformer coupling.
 6. Structure
 This unit was the first small and light-weighted caliber TV with transistorization, and all circuits were transistorized except for the high-pressure rectifier, that is, 47 transistors.  In addition to 27 diodes, we also added young semiconductor elements.
 Therefore, the power consumption is 30 W AC,
 20W at DC,
 Large 265 mm, heavy
 Screen mask type receiver 1/10
Many engineers have forgotten it because of the latent idea that it is not practical because of the actual situation, but due to the reduction of the screen it is enough.
 In addition to entering the area of ​​practical application, the circuit is made more transient, smaller and lighter in weight, has higher brightness, has high fidelity color reproduction, reduces unnecessary radiation, and simplifies and stabilizes the circuit.  In addition, the use of a single electron gun picture tube reduces the effect of the earth’s magnetism and the omission of the convergence yoke and its circuitry.  Is very easy to handle.
 Since it also contains many immature points, we would appreciate it if it could be improved with the criticism and guidance of the seniors.
 Finally, Mr. Tadashi Nakamura, Director of Video Management Division, Kobe Industry Co., Ltd., who was in charge of the development of the KARONETRON, and Mr. Narabi.  We would like to express our gratitude to Shigeru Shiga, Managing Director of Hachiyo Denki Co., Ltd.
 The brightness can be about twice as high as that of the 16-inch shadow mask, and the resolution is about 250.
 Get the brightness of
 Using this small-sized color-tron,
 The method of color reproduction with a TV receiver is as follows.
 Not only for color ITV, color VTR monitor
 Even if it does, it will bring out its features and give it an unprecedented amount of enjoyment.
 In addition, the future micromi
 Transistor circuit, Nikkan Kogyo Shimbun (1964)
 Along the direction of the network
 However, the application of the system is expected to expand more and more.
 Bean telop
 Color Net System Type 9 Color Image Receiver 〓 Paper
 We would like to thank Mr. Hiroshi, Mr. Isamu Mitani, Director of the Patent Office, for guidance and cooperation.
 And the fingers of everyone in charge of the engineering department
 (Reception on October 20, 1964)
 New York (1957)
 [Reference text]
 1) Shigeo Shima: To
 2) Fumio Mikuma: Transistor and Communication Engineering, Seibundo (1963)
 3) Editorial Committee: Television Engineering Handbook, Ohmsha (1959) 4) Masamitsu Kawakami: Electronic Circuits, Volume V, Kyoritsu Publishing (1958)
 5) J. W. Wentworth Color Television Engineering, McGraw-Hill,
 New York (1955)
 6) NTSC: Color Television Standards, McGraw-Hill, NeW York
 7) The Itazeltine Laboratories Staff: Principle of Color Television,
 John Wiley and Sons, New York (1955)
 8) D. G. Fink: Television Engineering Handbook, McGraw-Hill.


PDF article detailing the operation of the Yaou Colornet GTC-9.

An advertisement appearing in the December 13, 1965 issue of Electronics magazine featuring the Yaou Colornet GTC-9. Note, the photo still does not show the UHF tuner selector which was required to be included in domestic televisions sold at this time.


Corporate History
Established as Yaou Shoten Ltd. The company moves from the manufacture of radios, loud speakers, electric phonos, etc. into the manufacture of home electrical appliances
Company named changed to Yaou Denki Ltd. Kawasaki factory.
Company name changed to General Ltd.
Named changed to Fujitsu General Ltd.



A few new details surface about the Sony first generation Chromatron and the Yaou Colornetron in this two page article appearing in the January, 1966 issue of Radio-Electronics. View the PDF.


The best description thus far of the operating principles of the Yaou Colornetron CTC-9, courtesy Electronics magazine. View the PDF.


We also learned that the Yaou Colornetron CTC-9 was on display at the 1965 New York World Fair, Japananese Pavilion, Exhibit 29. According to Broadcasting magazine, you could not see or purchase the set unless you attended the pavilion. It is not clear if the set was for sale at the fair. As far as we know, not one set has surfaced in the United States. Below a portion of a hand out brochure.

Update, January 17, 2022





In 1966, Fairchild Semiconductor Co. designed this experimental 11 inch color Chromatron C6003 for Paramount Pictures. It was an all transistor set except for one rectifer tube. The details can be found here courtesy of Radio-Electronics June, 1966 issue. View the PDF.



French Chromatron Development

From Jerome Halphen:

I found a copy of the May 1967 issue of the French electronics magazine “Le Haut-Parleur” (the Loudspeaker) which for 7 decades was the authoritative publication in this field – sort of a French “Wireless World” (UK magazine).

I am sending you a scan of the article covering the description of the color grid tube developed by the CFT (Compagnie Française de Television) Henri de France’s research lab. Actual manufacture was accomplished by Thomson.

This 19″ tube had purity problems: the unsupported grid wires were not rigid enough and vibrated because of the deflection magnetic fields, thus degrading color purity. Lack of money and time prevented the CFT to perfect the design and industrial production never happened.

Apparently the patents were sold to Sony, and along with the other patents they purchased from Paramount – Chromatic Laboratories, formed the foundation upon which the Trinitron tube was developed.






Sony Chromatron 19C 80, (19C 90), 19C 100

* Update, July 21, 2014: Just found out from my online friend, Noriyoshi from Japan, that Sony manufactured two additional Chromatron models in 1967. They are the 19C 80 and 19C 100 both delta three gun, all tube televisions using the Chromatron wire selection grid. These two models were manufactured in 1967. The 19C 70 is also a delta three gun, all tube set. All three model use the same 19 inch CRT, 480AB22. Noriyoshi is currently repairing a 19C 100. Watch his progress here. See the below photos of the 19C 100, courtesy Noriyoshi Tezuka. More information to follow. Special Thanks to my friend Jerome for alerting me of this.

Update, July 22, 2014: A query to the Sony Archive Museum in Tokyo, Japan revealed the following:

“Chromatron color TV 19-c 80
Release date:1967/12/1
Price:\179,000+tax (at that time)

Chromatron color TV 19-c 100
Release date:1967/10/1
Price:\198,000+tax (at that time)”

Unfortunately, no original photos to display.

Update April 21, 2015

First photo of the Sony Chromatron 19C-80 found. It won the Good Design Award of Japan in 1968.


Sony Chromatron 19C-80 courtesy

Sony Chromatron 19C-80 courtesy

UPDATE, APRIL 19, 2018

Found a service guide for the 1967 Sony Chromatron 19C-80. More to come.


This is speculation, but we believe Sony marketed the 19C 80 and 19C 100 in Japan to appease the angry Sony dealers who did not have a Sony color set to sell, (Sony’s competition were selling shadow mask color sets years earlier) even while Sony was working behind the scene to develop the Trinitron.

(The Sony KV 7010U may have been an appeasement to U.S. dealers until the Trinitron was ready. More about the KV 7010U can be found below.)

Update, July 23, 2018

We searched the Paris Match Magazine archives and in the November, 1968 issue, we found these rare photos. The first photo shows Sony co-founder, Masaru Ibuka with his engineers working on the Chromatron/Trinitron project. In the background to the left, you can see the Sony KV 1310 Trinitron which had just been put on sale in Japan in October, 1968. What is very interesting, to the right you can see a working Sony 19C-80 Chromatron! This is the first such photo found.



In this photo, you can see the Sony KV 7010U Chromatron in the center below an unidentified television. We don’t see the tri-color ellipse logo, so it’s most likely the Chromatron.



1967 Sony Chromatron 19C 100 Photographed July 16, 2014 Courtesy Noriyoshi Tezuka

1967 Sony Chromatron 19C 100 Photographed July 16, 2014 Courtesy Noriyoshi Tezuka

Update May 26, 2015:

This Sony 19C 100 was recently discovered May, 2015 in an online Japanese auction which is now completed. The set sold for an undisclosed amount. The following photos give us additional details about the set.












Sony Chromatron Prototype

These two images were taken from my September 1967 issue of Popular Science magazine. In the first image, Sony co-founder Akio Morita on the right is demonstrating the newly developed Sony Chromatron 7 inch color television which main advantage is a very bright image, even under bright flood lights. Popular Science magazine reports this is to be the first Chromatron sold in the United States. The set was called “Microcolor”. * I believe the article is in error, because it it was well know that Sony gave up on the Chromatron in the fall of 1966. The Chromatron had production problems, yielding only 3 good tubes out every thousand. It sold for 198,000 yen ($550.00) in Japan, but cost Sony 400,000 yen to build each set. In Japan, plagued with problems, Sony sold only 18,000 Chromatrons from 1965 to 1966. (Information from the book “Sony”) I believe this television is a pre-production version of the 7 inch Trinitron introduced by Sony in 1968 and discussed below. You can see differences in the control arrangement, the carrying handle and smaller trim pieces on the sides from the final production version shown below.

* Update: The below images are indeed that of a Chromatron, however a modified redesign of the Chromatron. Because of the overwhelming problems of Sony’s Chromatron in Japan, financial losses from the Chromatron development and mounting pressure from Sony dealerships to introduce their first color set, Sony’s chief engineer and CEO launched an aggressive campaign to develop a new color tube. Sony took inspiration from the 1966 General Electric (GE) Portacolor and considered licensing the design, but in the end insisted that they design a new CRT which had the Chromatron benefits of high brightness. Early RCA color CRT’s and shadow masks blocked as much as 85% of the light energy. The Portacolor had a unique 3 beam, 3 gun, inline color CRT, but Sony engineers devised a way to create 3 inline beams within one gun for the first time. The three electron beams focused through the center of a newly developed single large lens instead of through three small lenses. This resulted in a much improved, focused image in the same way as a photographer closes the aperture of the lens, using just the center of the lens to obtain the sharpest image. The center of the lens is the sharpest. A side benefit is fewer convergence adjustments. In December of 1966, Sony developed the 7 inch Chromatron prototype as pictured below. Sony had to work out additional technical problems with the Chromatron, and it’s engineers worked day and night to meet a self imposed deadline: SUCCESSFULLY DEVELOP A NEW COLOR CRT FOR MARKET RELEASE BY OCTOBER 1968. They created a new type of shadow mask which had unbroken vertical slots or stripes instead of the round holes of a conventional shadow mask, allowing much more light to pass through. Sony called this mask the “aperture grill”. On the evening of October 15, 1967, the new tube, with the inline 3 beams, 1 gun, lens and aperture grill were assembled and tested. It was a success and a new color tube was born and named “Trinitron”. “Trini” for 3 electron beams, “tron” from Chromatron the original inspiration. On April 15, 1968, the Trinitron color television was announced at Sony corporate headquarters. Trinitron is the son, born from the Chromatron and the first color set to go on sale in the United States was the 7 inch KV 7010U Chromatron, followed shortly with the KV 7010UA which swapped out the Chromatron with the new Trinitron CRT, which is very similar to the Chromatron prototype as below. I wish to credit Sony and the author of the book “Sony” for some of this information. This writer had just graduated from high school in January, 1965 and went directly to work in his new career. I wanted to purchase my first color set in 1966. I spent months of evaluation on the color televisions available at that time. Zenith, Motorola, Magnavox, Slyvania, General Electric, RCA, Admiral, Packard Bell, Curtis Mathis and others were evaluated. Eventually, settled on the RCA as shown above, but was not satisfied with it. After seeing the first two Sony sets, a 7 inch and a 12 inch in 1968, I looked no further. They had the best color imaging available at the time and blew everything else away in my personal opinion. It was to me, a quantum leap improvement in quality.

Update July 11, 2012: I am now convinced that the below two black and white images are not that of a true Chromatron. Why? I recently acquired a copy of Sony’s 1967 annual report. Sony states that the below television is a Chromatron and was shown in the United States in June, 1967 and would be marketed in the United States in summer, 1968. We know that Sony gave up on the Chromatron in Japan in 1966 and set out to re-engineer the tube. We are looking at a modified Chromatron television in the two photos below which is the Trinitron. Sony called it a Chromatron in the Popular Science article and in their annual report, because it was not officially named a Trinitron until their April, 1968 announcement. You can see that in the 1968 color publicity photo, it was called Micro Color same as the prototype in the two black and white photos from 1967. You can see that the color 1968 publicity photo is virtually identical to the final released version of July, 1968, which was called a Trinitron.

* Update January 28, 2013: I was wrong. Just found a working Sony KV 7010U Chromatron! The set is being repaired and I will provide detailed information and photos soon.

After the Chromatron, nineteen years later, Sony succeeded in developing the first commercially available index beam television in the form of a one tube projection TV and rightfully renamed it the Indextron. After that, three years later in 1988 the first stand alone consumer available beam index color television called the WatchCube. You can read about it on the INDEXTRON PAGE.

The integrated antenna/handle design was carried forward in the 5 inch Sony Trinitron KV 5200 introduced in 1980 and shown on Page Two.

Sony Chromatron Prototype

Sony Chromatron Prototype

Sony Chromatron Prototype

Sony Chromatron Prototype


Sony’s Official Description Of The Problems Encountered Developing Chromatron.

Quoted directly from Sony’s History Website, Courtesy Sony Corporation.

“Overshadowing the exciting news of the Sony Building and successful foreign investment bids were the diligent efforts of the Chromatron development team.

Completed and announced to the public in September 1964, the Chromatron color TV was displayed at the Sony Building and was the focus of much attention. Nonetheless, mounting production costs and its tendency to malfunction made mass production unfeasible.

Numerous practical problems not addressed in Dr. Lawrence’s theory arose when producing an operational model. These included troubles derived from the use of high voltage and difficulties in insulating against it. The scanning stripes, which make up the fluorescent screen, must be so thin as to not be detected by the naked eye. At least 270 to 300 stripes are needed for picture resolution. When compressing the stripes, however, the space between the color switching grid wires must be proportionally narrowed. The precision needed to focus the electron beam through the narrowed grid requires high voltage. This, in turn, requires high performance insulation, which is technically difficult. Naturally, the insulation material must tolerate high voltage. The problems involved in determining what materials to use for insulation and how to affix it were not easily resolved. Since the insulated parts were set inside the cathode-ray tube, there were problems creating and maintaining the proper vacuum level inside the tube. The more tests they ran, the more problems they incurred.

To double the brightness of the picture, the development team devised aluminum film for the back of the fluorescent material. Due to high voltage, however, the thin aluminum film was often drawn toward the color-switching grid. As a result, the display would show dark spots in places where the coating had chipped and glittering patches where it had stuck to the grid. Eventually, as large sections chipped off and stuck to the grid, it would short circuit and the switches would stop functioning. Such electrical defects developed one after another.

To compound matters, etching the phosphor was much more difficult with Chromatron than with the shadow mask process. Compared to the optical printing method of the shadow mask process, which etched the phosphor stripes using the rectilinear propagation characteristics of light, the electron beam printing method used in Chromatron involved etching after the cathode-ray tube was assembled. This was extremely time consuming — in all, one phosphor stripe alone required from forty minutes to an hour to etch. Thus, even if a printing machine was in full operation 24 hours a day, it could only print 24 stripes a day. In order to meet demand within the eight hour working day, Sony would have to buy dozens of printing machines. In any event, it was not a very productive process.

There were no simple answers, research expenses continued to mount. Yoshida, Miyaoka and Ohgoshi, leaders of the Chromatron team, went through one difficulty after another. At this rate, Sony would never claim Chromatron color TV as its fifth innovative product. In fact, those involved considered it more of a “kuro-matron” than the Chromatron, “kuro” meaning struggle in Japanese,.

“Are you sure that the shadow mask doesn’t deserve reconsideration?” Ibuka suddenly brought this up at a board meeting. It seemed that the ever confident, resolute Ibuka had nearly lost hope. The Chromatron situation was that serious.

The more Chromatron sets they made the greater their losses. Pouring any more funding into the development of Chromatron seemed concomitant to “shinju” or double suicide.

“This is all my fault.” As president, Ibuka blamed himself for the Chromatron fiasco. Nonetheless, Ibuka had his pride — not so much as a businessman, but as an engineer. Now, if ever, was the time to back up his dejected engineering staff.

“Start looking for a process to replace Chromatron. This time I will act as team leader from start to finish.” This was Ibuka’s way of taking responsibility.

Morita provided vital support. He told Ibuka, “Don’t worry about funding. I will take care of it. Develop the project exactly as you wish.” From that day fourth, Ibuka went to the laboratories daily to oversee the new project.

In the summer of 1966, Yoshida went to the U.S. to research the market and to inspect the portable color television which General Electric had announced the previous year. This 13-inch set used a shadow mask system with three electron guns in-line. Yoshida received some inspiration from it, but decided that its technology could not easily be applied to sets larger than 13 inches. Yoshida found RCA’s advances even more startling. The brightness of their picture had greatly improved. This was due to the switch in fluorescent material from sulfide to rare metals. In addition, RCA was producing about 20,000 sets per month. Yoshida was amazed, especially considering the production rate of 1,000 a month at Sony. In his consideration, RCA’s set was a perfected product.

“If we can’t begin mass production by 1966, then we’ll have to give up the Chromatron and switch to the shadow mask system.” Upon receiving Yoshida’s report, Sony top management reluctantly gave the okay to consider the switch to the shadow mask process.

Yoshida, however, could not bear the thought of bowing to RCA’s technology. Nor did he intend to let the five years of hard work that the staff had devoted to Chromatron amount to nothing. There had to be some solution to this dilemma. Just when everyone else had given up hope, Yoshida offered a gamble of an idea in sheer desperation.

Taking a hint from GE’s portable TV, Yoshida suggested reforming the electron gun. “See if you can run three electron beams through a single electron gun.” The Sony staff was cool to the idea. It seemed from the beginning nothing more than an experiment to prove the futility of the idea. Miyaoka was among those who wondered whether “Mr. Yoshida had gone nuts.” Miyaoka grudgingly ran the experiment, in part, simply because it was an order from the top.

Common sense said it was impossible. But the results contradicted this. Upon hearing the results, Ibuka thought, “This sounds as though it’ll work! I think we should go with it.” Ibuka immediately called Miyaoka to ask whether he considered the new gun viable. Miyaoka really was not sure. On this day, however, he had a special reason to reply in the affirmative. Miyaoka was an avid cellist, and it was his rehearsal day. Any answer other than “yes” would have tied him up answering Ibuka’s questions and make him late for practice. So Miyaoka answered “yes” and left for practice.

In December 1966, the prototype of the new electron gun was completed. The test results on a seven-inch Chromatron set were startling — it gave the sharpest picture yet. With this, future prospects finally brightened.”

Authors Note: We believe the above mentioned seven-inch Chromatron is the prototype set shown just above in the 1967 issue of Popular Science magazine and as you will see later, went to final production in April, 1968 as the model KV 7010U. Yet, we have documented evidence that while the KV 7010U went to commercial market in April, 1968, almost immediately according to the April 29, 1968 issue of Electronics Abroad magazine, Sony decided to drop production of the KV 7010U and beginning in June (1968) start shipping the set with the Trinitron CRT, model KV 7010UA. For this reason, we say the KV 7010U was in production for three months or less. You will see further on in this article and on the Vintage Micro TV page, that my Chromatron KV 7010U is unit number 523. We know of another  KV 7010UA which has a Trinitron CRT and it is unit 1416. That is a difference of 893 units. Sometime after unit 523 and before unit 1416, Sony dropped the Chromatron CRT and switched to the Trinitron CRT.


“Next Ibuka and his team tested the effect of the new three gun in-line system on a shadow mask screen. The results were excellent. They worried, however, that using this with the shadow mask would dominate the new technology they had developed. Or worse yet, the new system might underscore their failure with Chromatron.

There had to be some way of incorporating the shadow mask’s merits into a process that provided even better quality than with the shadow mask done. Their reputation as innovators was at stake. Once again the entire engineering team gathered for days of brainstorming sessions. Despite his confidence in his engineers, Ibuka secretly worried whether it was not smarter to accept defeat and resort to another method. Before his troops, however, he remained dauntless and confident, always giving encouragement and inspiration.

Ohgoshi provided a needed breakthrough — the concept of the aperture grille. This grille consisted of narrow vertical stripes photo-etched onto a thin metal plate that was stretched over a frame. The electron beam penetration rate was 20%, a large improvement over the shadow mask’s 15% penetration rate. And the woven grille resembled the Chromatron. It was a lifesaver. Or so they thought for a short while.

Once again, problems appeared in the application stages. Due to the vibrating metallic tape in the aperture grille, the electron beam could not find its target. This resulted in uneven color. Ibuka, however, pulled Ohgoshi from this pinch. He merely stretched a couple of tungsten wires across the grille — a simple solution, but it did stop the vibrations.

Ohgoshi also took on the job of designing the glass envelope for the cathode-ray tube, by molding a model from gypsum. Usually a blueprint would be sent to a professional component company, but Ohgoshi insisted that it was simple enough to do by himself.

On the evening of October 15, 1967, the completed glass envelope was delivered to the plant. The research room was humming with activity — they were about to assemble the new cathode-ray tube. Each group of engineers worked silently on their allotted assignment: integrating the electron gun, affixing the aperture grille, applying the fluorescent material to the screen, etc. Finally, after degassing, the new cathode-ray tube was completed. By then, dawn was on the horizon.

After connecting the electrical circuits, a new color television was born. After final adjustments, it was finally tested. The incredibly bright screen overflowed with dynamic color. Everyone could only stare at the screen in silent amazement. Ibuka and top directors came running upon hearing the news.

“Everyone, it was quite a struggle, thank you…” Ibuka wanted to offer more words of encouragement, but could not. They had finally reached the end of a long and winding road. The new color television was named Trinitron — a compound derived from “trinity,” meaning the union of three, and “tron” from electron tube.
On April 15, 1968, The Trinitron was announced at a press conference at the Sony Building, where the reaction of both foreign and Japanese reporters was better than expected. At the end of the news conference, Ibuka made a comment that no one expected. “Trinitron will go on sale in mid-October, and by the end of the year, we’ll produce 10,000 sets.”

The research team member stood there stunned. No one could believe what was just said. They had just finished producing a mere 10 test models. How could they shift to mass production in less than half a year?

I’d like to wring his neck…” Yoshida scowled menacingly at Ibuka.
Ibuka, apparently heedless of the feelings of Yoshida and the others, assumed a look of nonchalance. His expression seemed to say,”I know you guys can do it.”



An article appearing in the January, 1968 issue of Electronics World magazine.

Courtesy Electronics World magazine

Courtesy Electronics World magazine


Sony KV 7010U Production Timeline Approximate.

December, 1966: Completion of prototype 7 inch Chromatron with first use of the one gun, three cathode system combined with the Chromatron wire selection grid.

Early, 1967: The new one gun, three cathode system is tested with a shadow mask, results reported to be excellent.

Mid, 1967: Concept of the Apeture Grill is devised.

June, 1967: The Sony prototype 7 inch “Micro Color” Chromatron is demonstrated to the press in New York City. Morita announces this set will go on sale in the United States in Spring, 1968.

October 15, 1967: The first prototype set combining the one gun, three cathode system with the Apeture Grill is assembled and tested successfully.

April, 1968: Morita and Ikuba announce in Japan, the invention of the Sony Trinitron Model KV 1310.

April, 1968: Gulf Western, parent company of Paramount Pictures Corporation, announces the 7 inch Sony “Micro Color” KV 7010U one gun, three cathode system with Chromatron wire selection grid, will go on sale in the United States in April, 1968.

April 29, 1968: Sony states, reported by Electronics magazine, that they will stop production of the KV 7010U Chromatron and beginning in June, 1968 start shipping the new 7 inch KV 7010UA with Trinitron CRT.

About August, 1968: Sony KV 7010UA Triniton go’s on sale in the United States.

Update, February 5, 2020


After the April 15, 1968 announcement of the Sony KV 1310U Trinitron in Japan, Sony embarked on a United States tour, demonstrating the KV 1210U Trinitron and KV 7010U Chromatron. The tour cities were New York, Miami, Chicago, Denver, San Francisco, Los Angeles and Hawaii and began May 15 to June 14, 1968.

Below, a photo of Mr. Onishi, Plant Manager, Osaka plant, 1st Manufacturing Dept., 3rd Section at one of the tour cities. Foreground, six Sony KV 7010U’s. Background, two KV 1210U’s.


Denver showing June 2, 1968.



This 1968 Sony publicity photo with live screen shot appears to be Model KV-7010U. It was photographed from my copy of the December, 1968 issue of Popular Mechanics. This is the earliest production model, later changed to the Model KV-7010UA with minor changes. This photo shows “Micro Color” with no three-color logo above the viewing screen. The sales brochure below, shows “Trinitron Color” with rectangular three-color logo above the viewing screen. A later version changed the three-color logo to the ellipse design.

1968 KV-7010U courtesy Sony Corporation

1968 KV-7010U courtesy Sony Corporation



Actual Sony KV 7010U Chromatron in operation in the hands of a Popular Science magazine editor. This image was scanned from the magazine and we tried to clean the photo the best we could.

Some interesting information can be gleamed from the magazine article.

1. The set is described as “Micro Color” not the Trinitron.
2. A diagram of the CRT shows a wire grid and described as such instead of the Aperture Grill.
3. The text of the article says “it has a grid of fine wires that give the tube high transparency.”
4. The article describes the CRT as being an “improved Chromatron developed by Dr. Lawrence.”
5. The article states “Sony took the Chromatron and added a raft of improvements that licked the production problems … and christened the tube Trinitron”.
6. The article further states “Sets currently on the market carry a list price of $429.95.”

This December, 1968 issue hit the news stands in November and we know magazine articles are usually prepared a month or two in advance of publication. Given that, we can say this particular model was on the market at least as early as September or October, 1968.

Question? Is the magazine article reviewing the KV 7010U Chromatron or the KV 7010UA Trinitron? I know of one set owned by a collector which is designated “Micro Color” without the three color logo, but is confirmed to be model KV 7010UA with a Trinitron CRT inside. Curiously in the October 31, 1968 Sony Annual Report, Sony states that a 7 inch Micro Color television was marketed in the United States July, 1968. They are silent as to whether it was the Chromatron or the Trinitron, but interestingly, in the previous year Sony Annual Report dated October 31, 1967, they stated that “a 7 inch Micro Color Chromatron will be marketed before Summer, 1968.”

Update, June 19, 2014: A careful examination of the photo in this magazine showing the rear identity tag reads ” Transistor TV Receiver”. This confirms that the TV under review was a KV 7010U Chromatron and because of the recent find of the KV 7010U service manual and other information recently found, we are now convinced that the author of this article was auditioning and reviewing a Sony Chromatron KV 7010U. The service manual recites: “7 inch, 90 degree deflection Chromatron system incorporating “Trinitron”. We now know that the KV 7010U Chromatron was released April, 1968 and the KV 7010UA was released approximately 3 months later.


This is one of the very few advertisements found for the Sony KV 7010U or KV 7010 UA. The set was only carried by specialty or high end shops. This ad discloses some interesting insights. First, the ad refers to the Popular Mechanics article as reviewed above. We confirm the set in the PM article was a Chromatron. Second, this ad states “Prototype on display at Beatty’s. Delivery within 6 months-will be between $350 & $430. … “ I have long thought the KV 7010U Chromatron was intended as a prototype for the soon to come, KV 7010UA Trinitron model, yet a few sets were sold to the public. (Less then 1000).

Speculation on my part. We know that the KV 7010U Chromatron was introduced in April, 1968 and then quickly removed from the market about July, 1968. We believe the “Prototype on display” at this store was a discontinued KV 7010U Chromatron. The store was talking about the replacement KV 7010UA Trinitron becoming available. However, we know the KV 7010UA Trinitron was already available by the date of this ad in other locations in the United States. The limited production probably explains why the set came to mid-America later.


As you will see below and on page one, Vintage Micro Television of this site, I found an actual Sony Chromatron Model KV 7010U.


We are showing information on the Sony KV 7010UA because it’s an improved Chromatron, renamed Trinitron and because cosmetically it looks identical to the KV 7010U except for the identity tag above the screen,  a logo and no logo and black mastic surrounding the Chromatron CRT. The Chromatron uses 55 watts, the Trinitron 65 watts and the Chromatron weighs 13 ounces less then the Trinitron.

The below photos identify the differences between the two televisions.


Sales Brochure from 1968 of the worlds smallest color television. In April, 1968, Sony introduced their first Chromatron and soon thereafter (July) Trinitron color TV for the U.S. market and the world’s smallest color TV at the time. It had a revolutionary new 7 inch CRT described in detail on PAGE ONE.

This is an original four page sales brochure of the first Sony Trinitron television sold in the United States, the seven inch KV 7010UA. It became available for sale in the Summer of 1968. I purchased new in spring of 1969.

Sony KV 7010UA Flier wordpress 525

Brochure Page two photographed December 30, 2011

Brochure Page Three photographed December 30, 2011

Brochure Page Four photographed December 30, 2011


Scans of vintage analogue 35 mm color print photographs taken shortly after acquisition of my original Sony KV 7010UA purchased in 1969.


Original Sony KV 7010UA scanned May 29, 2011


Live Screen shots from the moon photographed August 2, 1971 taken off the Sony KV 7010UA. The mission, Apollo 15, carried two astronauts, Commander David R. Scott and LM pilot James B. Irwin, the seventh and eighth men to walk on the Moon. These images are photos of the actual 35mm color prints I took on that day.

Sony KV 7010UA Screen Shot photographed August 2, 2011

Sony KV 7010UA Screen Shot photographed August 2, 1971

Sony KV 7010UA Screen Shot photographed August 2, 1971

Sony KV 7010UA Screen Shot photographed August 2, 1971

Sony KV 7010UA Screen Shot photographed August 2, 1971

Sony KV 7010UA Screen Shot photographed August 2, 1971

NEXT, (Amended August 3, 2016)

Two digital photos of original analogue 35 mm prints photographed 1971. Actual screen shots off the Sony KV 7010UA from the Tonight show in 1971, the first Carol Wayne, the second, George Burns. The original images were much sharper, these shots are digital photographs of 45 year old 35mm analogue glossy color prints made with a Nikon camera. Keep in mind these images were produced with 45 year old studio cameras, probably RCA TK-44’s.  Since then technology has progressed considerably. If we could ever find another KV 7010UA we will take screenshots and we are certain that today’s modern television cameras down converted to analogue will yield much better higher resolution images on this set. Still, back in this time period, this set blew away everything else on the market in terms of color picture quality. Having both the KV 7010UA and the KV 1210U in my possession at the same time, I will say the 1210U had a brighter, better focused image. I started taking screen shots back in 1969, being impressed with the picture quality of the Trinitron system. If you look closely at the photo of Carol Wayne, you can see the tri-color vertical unbroken phosphor stripes on the screen.


Sony KV 7010UA Screen Shot 1971

Sony KV 7010UA Screen Shot 1971



Sony KV 7010UA Trinitron

Finally found a replacement KV 7010UA on January 7, 2019. More information on the  Vintage Micro TV Page Two.


Sony KV 7010UA Photographed January 7, 2019


Original Sony KV 7010UA 4 color service manual, block diagrams, wave forms, etc. Drop me a line if you would like a copy.

Sony KV 7010UA Service Manual photographed May 30, 2011

Sony KV 7010UA Service Manual photographed May 30, 2011



“In 1967, Sony demonstrated a 7 inch Chromatron prototype according to a Sony press release on June 20, 1967. In Sony’s Annual Report dated October 31, 1967, Sony stated that a 7 inch Chromatron would be marketed in the United States before the Summer of 1968 and in Sony’s Annual Report dated October 31,1968, Sony confirmed that a 7 inch micro color was marketed in July, 1968. It appears that prior to the launch of the famed Trinitron CRT, an actual hybrid Chromatron with a 7 inch CRT was introduced in the United States as the model KV 7010U and then quickly replaced (within 3 months) by the model KV 7010UA with a Trinitron CRT. In January, 2013, a working Sony KV 7010U was found by this editor, currently in his possession and confirmed to be a hybrid Chromatron 7 inch CRT. The television was opened and among other things, a label was attached to the CRT bell reciting “SONY CHROMATRON Licensed under Patents of Paramount Pictures Corporation”.
A bit of mystery surrounds the introduction of the Sony KV 7010U Chromatron in April, 1968, only to be replaced so quickly (July, 1968) by the KV 7010UA with Trinitron CRT.”


*Update February 17, 2014:

Broadcasting Magazine January 15, 1968, reports: Gulf Western parent company of Paramount Pictures Corporation, holder of the Chromatron patent announced that Sony Corporation of Japan, would begin selling a 7 inch Chromatron color television in April, 1968.

Courtesy Broadcasting Magazine

Courtesy Broadcasting Magazine

Newspaper article from the Herald Statesman, Yonkers, N.Y., published February 3, 1968. It states that the 7 inch Sony Chromatron would be introduced on the U.S. market before Summer of 1968. This comports with all other research we found on the introduction date.


Then strangely in the the April 29, 1968 Volume 41 Number 9 issue of Electronics magazine it is reported that Sony has decided to drop the Chromatron CRT from the Sony 7 inch television and starting in June, 1968 would instead begin shipping a set “useing a tube right out of the laboratory” (the Trinitron model KV 7010UA). The reason given was that the one gun Chromatron requires hard-to-make color switching grids.

Courtesy Electronics Magazine

Courtesy Electronics Magazine

Almost immediately after the announcement (January, 1968) to introduce the 7 inch Chromatron in April, 1968, the decision was made to drop the 7 inch Chromatron and yet a few sets leaked into the marketplace. We wonder how many? We speculate less then 1000 from the evidence we have found thus far.

Update March 26, 2014: I think we solved the mystery. Sony’s purchase of a Chromatron non-exclusive license with Paramount Pictures read in part: to provide “technical assistance in the production of a chromatron tube and color television receiver utilizing it.” (Source, Sony History website) If we can find and read the entire agreement, we may find that Sony was contractually obligated to manufacture a Chromatron for the United States market and share technical information with Paramount who we know wanted to license to other U.S. manufactures.

Sony quietly dropped the Chromatron tube within 3 months of introduction and re-engineered the KV 7010 chassis with the Trinitron tube. (Source, Broadcasting Magazine)

Sony 7 inch Color Timeline


Sony Annual Report October 31, 1967

Abstract Sony Annual Report October 31, 1967. Sony will market a 7 inch Chromatron Micro Color television before the Summer of 1968.

Sony Press Release May 21, 1967

Sony Press Release May 21, 1968.

Sony demonstrates a 7 inch Trinitron color television in New York. Mr. Morita says “A 100% Sony development.” Due to be released here in August, 1968 at $430.

Sony Annual Report October 31, 1968

Abstract Sony Annual Report October 31, 1968.

In July, 1968, Sony introduced into the U.S. market, an all transistor 7 inch Micro Color TV set.

Courtesy Broadcasting Magazine

Courtesy Broadcasting Magazine.

I found this article about the 7 inch Chromatron in Broadcasting Magazine, dated June 26, 1967.

This photo was taken in New York on June 20, 1967 during the press conference which demonstrated the prototype 7 inch Sony Chromatron. Chairman and CEO Akio Morita with 7 inch Chromatron and experimental 1 inch black and white television. Courtesy New York Times.


Akio Morita with prototype 7 inch Chromatron. Sony to market 7 inch Chromatron in Spring, 1968. Will pay royalties to Paramount. Mr. Morita says some of their patents apply to the process and that all production problems have been solved. He also said the new Chromatron CRT is 85% efficient in luminosity.

Consider the time, it was 1967, no one had seen a color television this small. All other color televisions were using tubes (valves for the Brits out there 🙂 ) This model was all solid state and with a radical new Chromatron CRT. It was exciting.

It is also reported in Broadcasting Magazine, dated December 11, 1967 by Gulf & Western Industries Inc., New York (who acquired Paramount Pictures Corporation) that “the Chromatron color tube (patented by International Telemeter) would make it’s first appearance in the U.S. next year when Sony Corp. of Japan introduces it’s first color sets using the tube. Sony has an exclusive royalty license for the tube in Japan and a nonexclusive license for the rest of the world. At present, G & W is working with a U.S. TV-set manufacturer “that may lead to use of the Chromatron tube in sets produced by this company.”

A puzzling article published April 22, 1968 by Broadcasting Magazine. Here is an announcement of the 7 and 12 inch Sony Trinitrons in May, 1968 at the same time that Sony announced availability of the 7 inch Chromatron, “early Spring, 1968” or “July, 1968”. The Chromatron is model KV 7010U and the Trinitron is model KV 7010UA. The Sony KV 7010UA became available for sale approximately October, 1968. I saw this model in Sony’s Fifth Avenue, New York showroom, October, 1968.

Courtesy of Broadcasting Magazine

Courtesy of Broadcasting Magazine

Another confusing article published May 27, 1968 by Broadcasting Magazine. This article would suggest that the Chromatron was already on the market in May, 1968, confirming the 1967 Sony Anual Report dated October 31, 1967 that “Sony will market a 7 inch Chromatron Micro Color television before the Summer of 1968.” However, in the Sony Anual Report dated October 31, 1968, they state “In July, 1968, Sony introduced into the U.S. market, an all transistor 7 inch Micro Color TV set.” They are now silent as to whether it was a Chromatron or a Trinitron. Further this article states the first Trinitron would be a 7 inch model and would go on sale in August (1968).

Courtesy Broadcasting Magazine

Courtesy Broadcasting Magazine

RCA’s comment in the first above article is ironic with a bit of denial. The Sony Trinitron, born from the Chromatron, went on to be the most successful color CRT in history with a 40 year production run, creating enormous revenue for Sony and unfortunately RCA ceased production of their color sets and became defunct in 1986. Who owns RCA Records? You guessed it, Sony. It could have been different for RCA had they developed the LCD (liquid crystal diode) which they themselves invented and received first Patents. RCA failed to see the future of LCD and did not want to have a competing technology with their highly successful color CRT’s. More about this at the top of this page.

Reminds me of another time. Go back another 10 years to 1958 when RCA was ready to license the Aiken flat CRT technology. (See this article with photos) Citing from a 1996 IEEE interview with William Ross Aiken, inventor of the tube: “at the last minute, I guess at a Board of Directors’ Meeting for the final approval, somebody on the Board of Directors of RCA said, “Wait a minute, we’ve forgotten something. How are we going to explain to our stockholders that we wasted millions of dollars on the wrong tube?” And there was silence. And that did it. They said, “No, we will not take a license.” So then we went to other tube manufacturers. There were many in those days, and none of them would touch it because they already knew, like Philco, there would be a battle with RCA. “RCA will spend millions and millions, and lose money and lose money, until they put us out of the business. So we cannot go ahead.” So, nobody would take it.”

Interesting insights to learn how Sony accomplished their amazing success can be found in the book “Sony Style”.

I also found a reference in the book, The History of Television, 1942 to 2000 by Albert Abramson on page 118, wherein the modified 3 beam Chromatron is called “Chromagnetron.”

Based on the above, a bit of mystery surrounds the 7 inch Chromatron and why it was introduced, only to be replaced so quickly, within a few months. This writers opinion is that Sony engineers felt that they finally perfected the Chromatron in the form of the KV 7010U and wanted to demonstrate their technical expertise by marketing the 7 inch Chromatron in the United States, even though the Trinitron was nearly ready for production and because they were awaiting final patent approval. This and the fact that there was tremendous pressure by their shareholders and Sony dealers to introduce Sony’s first color television. Sony was years behind their competition trying to perfect the Chromatron when they could have easily adopted the standard RCA shadow mask system. As discussed earlier, Sony’s Chairman deemed the RCA system inferior and refused to imitate. Sony was a company of engineers as well as it’s co-founder Ibuka. Sony was an innovator as outlined in their founding prospectus. In the end, we believe that Sony could have continued marketing the Chromatron in the United States, but it would have made no sense for them to do so. They would need to continue paying royalty rights to Paramount or it’s successor and the Aperture Grill and associated components were easier to manufacture and similar to the fine wire selection grid, although not as efficient and Sony could patent their own exclusive Trinitron design which solved all the problems of the Chromatron.

Update July 24, 2020: Base on the below Chromatron serial number of 523 and the oldest known KV 7010UA Trinitron serial number of 1416, we can see that probably less than 893 KV 7010U Chromatrons were manufactured. This number may change with future finds of early KV 7010UA’s.

Known Sony 7 inch color televisions:

1. Owner: Author, Sony KV 7010U Micro Color, no logo, Chromatron, Serial Number 10523.

2. Owner: Author, Sony KV 7010UA Trinitron, rectangular logo, Serial Number 11416.


3. Owner: J.H. Paris, France, Sony KV 7010UA Micro Color, no logo, Trinitron, Serial Number 11584.

Sony KV 7010UA Owner J.H. Paris, France

4. Owner: Showplace Antique Center c/o C.M., New York, Sony KV 7010UA Trinitron Color with rectangular logo, Serial Number 12290.


5. Owner: Author, Sony KV 7010UA Trinitron Color, rectangular logo, Serial Number 12335.


6. Owner: Michael Jung, Germany. Ebay sale, October 28, 2018. Serial number 12391. KV 7010 UA Trinitron. Rectangular logo.


Sony KV 7010UA Trinitron Color, Owner Harry Poster, New Jersey, with rectangular logo, Serial Number 12830.


8. Owner: C. Murray, Los Angles Sony KV 7010UA, Trinitron Color with oval logo, Serial Number 13190.

Sony KV 7010UA photographed December 25, 2011 by C. Murray

9. Owner: Author, Sony Trinitron Color with oval logo, Serial Numnber 14261.


A note on the serial numbers. The first digit represents some sort of control number. These 7 inch colors sets were limited edition models and only available in the United States and Canada. When Mr. Ibuka announced the Sony KV 1310 in Japan (model KV 1210U domestically) in May, 1968, he said 10 thousand units would be available by October, 1968. His engineers thought this number was impossible to achieve. Also consider that the KV 1310 (KV 1210U) were mass produced for world wide distribution, not a limited edtion model. It has been reported that Sony achieved their goal and the first KV 1310’s  went on sale in Japan in October, 1968. The KV 1210U was not available in the United States until Spring, 1969. While it may have been possible, we believe it was very unlikely that my set for example with serial number 10523, would have been the ten thousand five hundred twenty third edition. The Model KV 7010U had a production run of approximately 3 months, therefor we believe this model was the five hundred twenty third edition. Based on the second model in the above list with serial number 11416, we know that Sony switched to the Trinitron CRT in this particular set. There is a difference of 893 units between my Chromatron and this Trinitron. The question is, at what point in the serial number sequence, did Sony switch to the Trinitron CRT? We would appreciate further information or correction from readers of this article.

UPDATE: January 28, 2013

The first Sony color television imported to the United States was a Chromatron!  You read about it on Visions4 Magazine.

A very special television for collectors because it was introduced April, 1968, being the first production Sony color model to go on sale in the U.S. market and it uses a Chromatron CRT instead of the Trinitron CRT. It is fully described on Page Five Trinitron. Apparently, the KV 7010U was only marketed for 3 months, possibly less then that. Starting approximately August, 1968, the first of two later production models were introduced as the model KV 7010UA. These models had major and minor changes, the first renamed the set from “Micro Color” to “Trinitron Color” and added a rectangular three color logoSony Trinitron Color Rectangular Logo 300_edited-1 and the second changed the logo to the ellipse design.

Sony KV 7010UA elipse logo Sony KV 7010UA ellipse logo

These two later production models were modified, changing to the newly developed Trinitron CRT. The KV 7010UA model was discontinued in 1970 and both the KV 7010U and KV 7010UA are extremely rare to find today, so I believe the production numbers were limited.

When introduced, this model was the smallest, lightest (18 lb. 14 oz.) color television in the world and produced the sharpest, best focused, brightest, most realistic color image available. It set a new standard for color reproduction. Soon production studios, television control rooms, hospitals and research facilities would be using the Trinitron color CRT as monitors.

I purchased my first model, the KV 7010UA in spring, 1969 still working well in 2006 when my wife mistakenly gave it away to charity, so after a 4 year search, was happy to find (January 16, 2013) this model which turned out to be an earlier model then my original and a Chromatron to boot.

The set features low power consumption 65W Max., sharp corners on screen face, quick start, integrated color-contrast control, sharper focus, greater brightness, automatic color control, no set up adjustment (For the KV 7010UA, Sony reduced the convergence controls from 12 to 2 and one is available for the user at the rear of set) and fully transistorized, 49 transistors, 32 diodes. The screen is 6 1/2 inches and the set measures 8 11/16″ W x 10 1/16″ H x 13 1/2″ D.

This diagram illustrates our belief that this television uses a one gun, three beam inline system. The Trinitron was under development, but not yet ready when the KV 7010U was introduced.

Courtesy Sony Corporation

Courtesy Sony Corporation

(Sony considered licensing the Trinitron, it was designed to work with the Chromatron, Trinitron and Shadow Mask systems.) If anyone has more information about the history of this model, please drop me a line.

*Update February 17, 2014:

Broadcasting Magazine January 15, 1968, reports: Gulf Western parent company of Paramount Pictures Corporation, holder of the Chromatron patent announced that Sony Corporation of Japan, would begin selling a 7 inch Chromatron color television in April, 1968.

Courtesy Broadcasting Magazine
Courtesy Broadcasting Magazine

Update March 26, 2014: I think we solved the mystery. Sony’s purchase of a Chromatron non-exclusive license with Paramount Pictures read in part: to provide “technical assistance in the production of a chromatron tube and color television receiver utilizing it.” (Source, Sony History website) If we can find and read the entire agreement, we may find that Sony was contractually obligated to manufacture a Chromatron for the United States market and share technical information with Paramount who we know wanted to license to other U.S. manufactures.

Update April 6, 2014:

On January 27, 1969, Gulf Western Industries, who purchased Paramount Pictures, sued Sony for alleged failure to share technical information pursuant to the 1964 license agreement and also on the Trinitron. (In 1961, Sony secured an exclusive license to develop the Chromatron in Japan only. In 1964, Sony obtained a non-exclusive license for the rest of the world.) We reviewed the case in the U.S. District Court Southern District of New York and read the Complaint and Sony’s Answer. Sony alleged that Great Western breached the Agreement by licensing the Chromatron Patents to Philco-Ford in 1967 without notice to Sony per the 1964 Agreement. Both the 1964 and 1967 Agreements were made part of the case as exhibits. The case was settled and discontinued with prejudice by both parties, by Stipulation filed December 9, 1969.

The 1964 license agreement did not contractually require Sony to manufacture a Chromatron in the United States or anywhere else as I had speculated.

The 1964 license agreement outlined that Paramount would be keeping track of the numbers of Sony Chromatrons sold for royalty purposes. Today Viacom is the successor in interest to Gulf Western and Paramount Pictures is a division of Viacom, so we may find the actual production numbers of the Sony KV 7010U (which I suspect is less then 1000 units) if we are allowed to check the archives of Paramount Pictures Corporation.

Interesting to note that Philco proposed another one gun system called the Apple tube now known as the Indextron in the early 1950′s. They worked on this tube for over 10 years without success.

So in 1967, Philco was still interested in an alternative to RCA’s shadow mask system, this time working on the Chromatron. I had not known this until reading the lawsuit.




Sony KV 7010U Chromatron also known as the Chromagnetron

Probably the rarest and most intriguing television in my collection, combining the Trinitron one gun with the Chromatron wire selection grid CRT. The complicated and troublesome color switching is eliminated, however PDF or post deflection focus of the three cathodes is retained.

Quoting Electronics World magazine, JANUARY, 1968: “The Chromatron used in the new Sony color receiver has three color guns, but uses them to form one beam. That beam is switched at a 3.58-MHz rate which offsets it just at the moment it crosses each stripe, so that the beam strikes and activates only the colors contained in the chroma signal”. Quoting another magazine, Radio-Electronics, January, 1966, “The Chromatron uses three electron guns, not in a different principal of operation, but simply to increase available electron current and brightness. So, in a literal sense, the present Chromatron (being at the time, the prototype 7 inch set) is a single beam, three gun tube”.

The April 29, 1968 issue of Electronics magazine describes the theory of operation: “the Chromagnetron, a one gun tube that employs the simplified color selection grid of the three gun version. The problem here was that the Chromagnetron only works well in a line sequential system and requires switching at about 3.58 megahertz. It uses two color switching yokes, one to separate the beam so that it appears to originate at different sources, and the other to cause the beam to reconverge on the faceplate. Instead of making one cathode do the work of three, Sony engineers decided to add two more, placing them where the other two beams in the Chromagnetron appeared to come from, in this way the Trinitron evolved.”

Note, these two magazines are commenting about the prototype 7 inch Chromatron and the third is commenting on the dropped Chromagnetron. We believe with some certainty, that the KV 7010U has a one gun, three inline cathode tube or Trinitron, combined with a Chromatron color wire selection grid. But the Electronic magazine comments create doubt. Clearly we know that according to Sony in December, 1966, the concept of the one gun, three inline cathodes combined with the Chromatron color wire selection grid was proven in a laboratory prototype, which then was demonstrated to the American press in June, 1967. Does this Sony KV 7010U really use a one gun, one beam CRT? In this authors opinion, either Electronic magazine was commenting on another prototype which might have been the Yaou Chromatron (Sony apparently recruited the entire engineering department of Yaou to help with the Sony Chromatron) or they misstated the principal of operation. We have observed on the KV 7010U chroma video board, there is a 3.58 MHz Xtal present which is not on the KV 7010UA Chroma board, but the complicated switching appears to have been eliminated. We would appreciate reader comments.

Trinitron one gun, three inline cathodes with Chromatron wire selection grid CRT. Technically know as the * Chromagentron, but referred to in the press as Chromatron. Since we have learned that the previous Sony Chromatron’s marketed in Japan (19C 70, 19C 80, 19C 90 and 19C 100) all had three gun delta CRT’s, this Sony KV 7010U is the purest in concept to the original one gun without shadow mask prototype Lawrence Tube or Chromatron.

Consider this: We now know that after Sony gave up on the the original concept one gun Lawrence tube because of the many problems encountered and that by December, 1966, they successfully completed the prototype 7 inch Chromatron with Trinitron gun. This prototype was ultimately released to the public as the KV 7010U shown below. Remember that the original Lawarence tube as patented was designed to be both one and three gun tubes. Dr. Lawrence acknowledged that the three gun prototypes he created were brighter. Consider that Sony compromised after abandoning the one gun Chromatron and produced four different models using delta three gun Chromatrons for sale in Japan only, so that their dealers could finally sell a Sony color television product. These delta three gun Chromatrons were essentially the same concept as the Lawrence three gun Chromatron tube and required the standard convergence requirements as all delta three gun designs. (See the IEEE WHITE PAPER AND PATENT) Consider that with the 7 inch prototype, Sony managed to create three inline RGB cathodes into a single gun and combine it with the Chromatron wire grid. A remarkable achievement! Sony had the best of both worlds, three inline cathodes in one gun with PDF Chromatron creating a brighter color image then a one cathode, one gun Chromatron. The 7 inch KV 7010U presented below was the genisus of Trinitron which in realty is an improved iteration of the original Lawrence tube.

If it sounds like I’m gushing, yes we are gushing.😄😄   Since finding the Sony KV 7010U, we found some truly outstanding sets such as the ultra rare Sony IDX-5000 Indextron with serial number 17, a JVC field sequential color television or an RCA 21CT55. But we consider this Sony Chromatron at the pinnacle and pride of our collection started in the mid 1960’s.

* Chromagnetron described in Electronics magazine, April 29, 1968, Electronics World July, 1968, The History Of Television 1942 to 2000 and in New Scientist magazine.

Sony KV 7010U

Update January 16, 2013

I finally found a replacement model after a 4 year search. My original model the KV 7010UA, was given mistakenly to Goodwill by my wife. The KV-7010U is the earliest production model using a Chromatron CRT and later modified by the Sony KV-7010UA with minor cosmetic changes, and swapping out the Chromatron CRT for the newly developed Trinitron CRT. See page one of the timeline, “Vintage Micro TV” for the story, then come back here for repair information.


February 14, 2013:

I asked Andy Cuffe who recapped my two Indextrons to try and restore the Sony KV 7010U.

Sony KV 7010U Blue Screen prior to restoration January 28, 2013

Sony KV 7010U Blue Screen prior to restoration January 28, 2013

When found, it had a blue screen with no image and static sound. Because a name and address sticker was placed on the bottom of this set, we were able to find the original owner who was a Doctor who practiced in mid town Manhattan, New York City. He used the set in the waiting room of his office. It was used extensively every day. There is more to this story which will be told later. Because of privacy concerns, we can only say the former owner of this television is related to one of the Chromatic Labratory engineers who worked on the original Chromatron under the auspices of Paramount Pictures Corporation!

After opening the cabinet, it was a great surprise to see this:

Sony KV 7010U CRT Label photographed February, 2013 by Andy Cuffe

Sony KV 7010U CRT Label photographed February, 2013 by Andy Cuffe

Sony KV 7010U CRT Label photographed February, 2013 by Andy Cuffe

Sony KV 7010U CRT Label photographed February, 2013 by Andy Cuffe

A Sony Chromatron licensed under patents of Paramount Pictures Corporation! I was estatic. Prior to this time, a Chromatron in a U.S. production KV 7010U was rumored but never verified to my knowledge. I have never seen a single piece of information to verify this other then Sony’s 1967 Annual Report which stated that a 7 inch Micro Color Chromatron would go on sale before the Summer of 1968 and a photo of a prototype was published in a Popular Science September, 1967 issue.

After Andy’s examination, he wrote: “This is just speculation,
but I think instead of an aperture grill it uses fine wires to focus
the beams onto the correct phosphor stripes. I expect that there is a
pair of fine wires running vertically behind each set of three
phosphor stripes. The wires form a lens that focuses the beams onto
the correct phosphor. It would need a second HV supply because there
needs to be a difference of maybe 500-1000v between the adjacent

After further examination Andy wrote:

“I can’t see much inside the CRT, but there is a small gap where there is clear glass near the front of the CRT. You can see a little of where the aperture grill would be. It looks very similar to an aperture grill, but the wires are much finer. I will try to photograph it, but I don’t think it will turn out because there are a lot of obstructions and the glass isn’t completely smooth.”

“I suspect they are applying a DC voltage to the wire mesh and only using
it to focus the electron beams onto the correct phosphor stripes. This
is simpler than trying to switch a single beam from stripe to stripe.
Since the wires focus the beams onto the correct stripes (rather than
just blocking them from hitting the wrong ones) it should make the
picture brighter.

I found the Sam’s folder for the 7010UA which has lots of pictures in
it. Most of the boards look identical. The HV circuit lacks the second
HV rectifier, and the CRT bell is a different shape. It also has a
standard set of purity rings instead of the electronic control. The
purity control on your set is probably varying the bias on the wire mesh.”

Andy performed a test on the CRT and found all three beams weak, the red especially so. Andy said a good beam emission should test at .85 on the meters, see next photo:

Sony KV 7010U Gun Test

Sony KV 7010U Gun Test

Andy continues:

“I’ve fully recapped both the main circuit boards, and the picture has improved (see the attached screen shot). I still need to replace a few more caps on the main chassis, but probably nothing that will make much difference the picture.

The severe color noise is gone, and the picture has better contrast. There’s still virtually no red though. Each color has two controls. Background works like the brightness control, and drive works like the contrast control. I have the red drive and background controls at maximum. The green drive is at minimum, and the blue drive is turned up just enough to balance the green. The blue and green backgrounds are set to produce proper black level. I think this is about as good as it will get with the bad red gun. I could try to rejuvenate just the red. The red is so bad that I think it will either do nothing at all, or improve it slightly. The only risk is that something unforeseen could happen to the blue, or green in the process.

I suppose if you’re really serious, you could see if RACS in France can rebuilt it. It would be similar in complexity to rebuilding a 15GP22 (minus the leaking problem).”

We decided against rejuvenation, deeming it to risky with little chance of improvement.

46 capacitors were replaced.

Sony KV 7010U Capacitors photographed March 19, 2013

Sony KV 7010U Capacitors photographed March 19, 2013

The next series of photos (a summary of 178) were taken by Andy in his shop except the last three screen shots taken by this author. I have many more to numerous to post, but if you are interested, I can send you full size, detailed images, just drop me a line.

Sony KV 7010U CRT face 2

Sony KV 7010U inside 1

Sony KV 7010U inside 2

Sony KV 7010U inside 3

Sony KV 7010U inside 4

Sony KV 7010U inside 5

Sony KV 7010U inside 6

Sony KV 7010U inside 7

Sony KV 7010U inside 8

Sony KV 7010U inside 9

Sony KV 7010U inside 10

Sony KV 7010U inside 11

Tap or click on next image for full view.

Update August 2, 2022: A video of the Sony KV 7010U in operation yesterday. Tap on below image.

Sony service manual found by Andy Cuffe on June 14, 2014. Tap or click on image for enlarged view or view the PDF.


I want to thank Andy Cuffe for his expertise and help in restoring this television.

Now you can read about the design of the 1964, one gun Chromatron prototype and the 1965 Sony Chromatron 19C 70 in the below 15 page PDF file. Some of the information applies to the design of the Sony KV 7010U. I want to thank the staff at Sony Archive History Museum in Tokyo, Japan for sharing this document. I know it will be of interest to television and history enthusiasts worldwide.

Update: July 28, 2022

Nine years later, we now have the service manual for the Sony KV 7010U Chromatron and I got brave enough to open the cabinet and tweaked the drives, cleaned the tuner and replaced an antenna wire which looked deteriorated.  I found a new Digital Stream digital converter box which has RCA A/V outputs. I set the box and channel selector to channel 4 and used an OTA signal from Phoenix PBS channel 8.5. All three inline cathodes within the single gun measure extremely low emissions, especially the red.  The last two photos give an expression of the bad red, but we were still able to get reasonably bright images, a testament to the lack of a shadow mask or aperture grill.  The colors are not accurate, but watchable.  I don’t believe I posted screenshots prior, so see 4+2 static images below. Photos shot with an iPhone X, processed with Affinity Photo editor.



Click or tap image to download PDF

Courtesy Sony Corporation

1964 Sony 19 inch one gun Chromatron prototype. Note: It is not know with certainty that the television shown in the below photo is the one or three gun version. We can say that the cabinets in the photo match up well with the dememsions of the one gun described in the Press Release, whereas the three gun version was a vertical upright cabinet as shown previously above.


Now jump back to the Time Line on page one “Vintage Micro TV”  to read the story with photos and screen shots of the Sony KV 7010U.

This New York Times article dated September 9, 1964, corresponds to the above Sony press release, courtesy New York Times.

Courtesy New York Times

Courtesy New York Times

THE ONE GUN 17 inch Sony Chromatron went into pilot production. * In 1965, the following year, Sony decided to market a 3 gun, 19 inch Chromatron. This set sold in Japan only, during 1965 and 1966, and shown above on this page, as model 19C 70. Also, it is widely reported that this model sold only 13,000 units. I found a 1994 IEEE interview with one of Sony’s chief engineers of the Chromatron/Trinitron, Susumo Yoshida, which said, in part: “It was beautiful. The Chromatron is beautiful, bright, and sharp, if it works. If it can be mass-produced, it is a fantastic product. They only produced EIGHTEEN THOUSAND SETS, and it was nice, bright, clear, and sharp. People really appreciated the product. There was even a lifetime guarantee by the Sony Corporation. If it was broken, customers could ask Sony to fix it for free.”

What we have learned is that Sony continued to have technical problems. It was a manufacturing nightmare and nearly drove Sony to bankruptcy. Masaru Ibuka, Sony’s co-founder and President refused to give up on the Chromatron. He did not want to copy RCA’s shadow mask system, which he deemed inferior. “We must produce something different. We do not copy … We are a company of engineers.” Indeed it was written in the company’s founding prospectus which Mr. Ibuka drew up in 1946.

Mr. Ibuka finally thew in the towel in Fall, 1966. He looked for a new solution to the Chromatron, and assembled a core group of engineers who were given the task of correcting the Chromatron’s problems. They worked 24/7 and experimented with various techniques. This led to the developement of the Trinitron CRT. In many ways, the Trinitron resembled the Chromatron. It had one gun, but this time with 3 inline beams within the single gun structure. It had the vertical phosphor stripes etched across the screen like the Chromatron. The new “Aperture Grill” was aligned with unbroken vertical slits, much like the Chromatron’s wire selection grid. The Aperture grill was not as efficient as the Chromatron wire selection grid, but still was 3 times brighter then the shadow mask dots and holes system. The Trinitron required only 2 convergence adjustments, instead of the 12 used in the shadow mask system. This made the Trinitron an instant success, together with superior beam focusing through one large lens instead of three small lenses, less parts, and lower power consumption. The superior image was instantly recognized by all who saw it for the first time.

Some will say, that if Sony does not copy, well then why did they introduce the Lawrence Chromatron? Possibly one could say they imitated, and brought to consumers the Chromatron system, which no other company was willing or able to achieve before them. That was approximately *18,000 units brought to market with a lifetime guarantee, not to mention the Chromatrons sold in the United States as the KV 7010U. This led to a very similar Trinitron CRT becoming the most successful color television in history with a 40 year production run.

Update July 21, 2014: *It is unclear if the total production of 18,000 units represents the production of only the 19C 70, or the combination production of the 19C 70, 19C 80, 19C 90 and the 19C 100. The 13 to 18 thousand figure came from research on the 19C 70 which was manufactured 1965 and 1966 in Japan only. The 19C 80, 19C 90 and 19C 100 were manufactured in 1967 with an unknown production run, therefore the total production of Sony Chromatrons could be much higher then the 18,000 figure.

* Citation: It is noted that the original Lawrence Chromatron CRT was specified in both one and three gun versions. “Described in this paper is a single gun and three gun version of a simple color cathode-ray tube developed by Chromatic Television Laboratories, Inc., based on the ideas of Dr. Ernest O. Lawrence of the University of California. Both types utilize post deflection focusing (PDF) and acceleration as will be discussed in the body of this paper. The principles described are quite general and may be applied to other cathode-ray tube and camera tube designs. The single and three gun types discussed below will operate with any of the presently proposed color television transmission systems.”

Published in:
Proceedings of the IRE (Volume:41 , Issue: 7 )

Date of Publication: July 1953

851 – 858
Digital Object Identifier :
Date of Current Version :
08 January 2007
Issue Date :
July 1953


On January 27, 1969, Gulf Western Industries, who purchased Paramount Pictures, sued Sony for alleged failure to share technical information pursuant to the 1964 license agreement and also on the Trinitron. (In 1961, Sony secured an exclusive license to develop the Chromatron in Japan only. In 1964, Sony obtained a non-exclusive license for the rest of the world.) We reviewed the case in the U.S. District Court Southern District of New York and read the Complaint and Sony’s Answer. Sony alleged that Great Western breached the Agreement by licensing the Chromatron Patents to Philco-Ford in 1967 without notice to Sony per the 1964 Agreement. Both the 1964 and 1967 Agreements were made part of the case as exhibits. The case was settled and discontinued with prejudice by both parties, by Stipulation filed December 9, 1969.

The 1964 license agreement did not contractually require Sony to manufacture a Chromatron in the United States or anywhere else as I had speculated.

The 1964 license agreement outlined that Paramount would be keeping track of the numbers of Sony Chromatrons sold for royalty purposes. Today Viacom is the successor in interest to Gulf Western and Paramount Pictures is a division of Viacom, so we may find the actual production numbers of the Sony KV 7010U (which I suspect is less then 1000 units) if we are allowed to check the archives of Paramount Pictures Corporation.


Interesting to note that Philco proposed another one gun system called the Apple tube now known as the Indextron in the early 1950’s. They worked on this tube for over 10 years without success.

So in 1967, Philco was still interested in an alternative to RCA’s shadow mask system, this time working on the Chromatron. I had not known this until reading the lawsuit.


Perhaps a French speaking viewer could translate this November, 1977 magazine article. Tap any image to enlarge.

UPDATE, APRIL 30, 2016

My friend, Jerome Halphen and myself were scheduled to give a joint presentation on the Chromatron CRT technology at the annual convention, sponsored by the Early Television Foundation, Hilliard, Ohio. This year it was held from April 29 through May 1, 2016. Unfortunately, because of unforeseen personal circumstances, I could not attend. We had to cancel our flight and room reservations at the last minute.

Here you see Jerome giving the presentation at the MaKoy Center in Hilliard. He used this page of this website you are reading now to present a Power Point slideshow. He filled in for me admirably, thank you very much Jerome and thanks to Wayne Bretl for the photos.



In 1951, Dr. Lawrence invented the Chromatron and said the Chromatron could be marketed as both, one and three gun versions. He said the three gun would be brighter and partnered with Chromatic Television Laboratory. Paramount Pictures Corporation, holder of the Chromatron patents, never intended to produce the Chromatron on their own, rather they tried licensing deals with American and Dutch companies. None of these companies were successful in bringing a Chromatron television receiver to the consumer market until Paramount entered into an agreement with the Sony Corporation of Japan.

In September, 1964, when Sony announced to the world that they were ready to market the first Chromatron television receivers they announced the three gun 480AB22 CRT and described it as a “high class, highly luminous” CRT and simantantiously, they also announced and demonstrated a prototype one gun Chromatron CRT without a model number and described this CRT as a common class, affordable CRT. The next year in May, 1965, Sony introduced the company’s first color television receiver. It was the model 19C-70 delta three gun Chromatron using the 480AB22 CRT which sold only in Japan in 1965 and 1966. Then in 1967, they introduced three more delta three gun Chromatrons, using the same CRT, models 19C-80, 19C-90 and 19C-100. These four models were in my personal opinion compromise solutions. They required the conventional convergence boards as in shadow mask television sets. They did offer superior, highly luminent images because of the high transparency of the Chromatron wire color selection grid.

From the very beginning, Sony tried  to perfect the one gun Chromatron that was demonstrated at the September, 1964 press conference and which went into pilot production, but not final production. This is the set that gave them all the problems and nearly bankrupted the company. This is the prototype set that received all the press. Sony gave up on this prototype in mid 1966 and set about finding an alternative which ended up being the famous Trinitron.

Curiously, an engineering prototype 7 inch color set, using the newly invented one gun, three cathode tube, combined with the Chromatron color selection wire grid, actually made it to the American market in April, 1968. This was about the same time as the Trinitron announcement in Japan in April, 1968. This 7 inch Chromatron was model number KV 7010U. Within approximately one month, Sony decided to terminate the KV 7010U Chromatron and shortly thereafter, introduced a near identical set, but instead, it used the newly invented Trinitron CRT, model KV 7010UA. This was the first Trinitron sold in America and appears to have come to the market just prior to the first Trinitron (KV 1310) announced for sale in Japan in October, 1968.

The Sony KV 7010U, a most interesting engineering curiosity that somehow made it to the American market and then, quickly terminated.

At the dawn of color broadcasting in 1953, the Chromatron CRT was one of the competing systems along with CBS and RCA. RCA won the competition with it’s compatible color dot and shadow mask system and introduced it’s first color television, the CT-100 in April, 1954. Ironically 14 years later, Sony introduced the Trinitron system very similar in concept to the Chromatron and in doing so, they filed more then 100 new patents to perfect and improve upon the original Chromatron. Sony achieved their goal and created a unique television technology which dismissed the licensing rights which Sony would have been required to pay to the inventors of the three gun shadow mask and Chromatron systems. This system was instantly recognized by all who first saw it as superior, it was rewarded with an Emmy award and became the most successful television product in the world with a 40 year production run.

After pioneering the color television industry, it was sad to see the demise of RCA in 1986. The Radio Corporation of America deserves great credit for all their endeavors and *inventions to enhance the entertainment experiences of the American people and abroad.


* Actually for history, Philo Farnsworth was awarded priority of inventions for both his image dissector, (1930 and confirmed in 1934 after all appeals by RCA were overturned by the appeals courts and the Supreme Court) dating back to 1927 and the image orthicon (1933) by the U.S. Patent office. Because RCA was determined to go forward with the commercial manufacturing of television equipment, RCA reluctantly entered into a cross-license/royalty agreement with Farnsworth in 1939 after their loss in court, spending years of litigation fighting Farnsworth’s inventions. Farnsworth was honored at the 2002 Emmy Award Show in this clip. In March, 2013, Philo Farnsworth was posthumously inducted into the Television Hall of Fame by the Academy Of Television Arts & Sciences for his invention of the all electronic television. His likeness is memorialized at Statuary Hall at the U.S. Capital Building, Washington, DC.


The vision for electronic television came to him as a 14 year old farm boy plowing the potato field of his parents farm. The furrows in the plow field represented scan lines in his mind. Watch this one hour documentary about a quiet manimage who battled the corporate giants of Wall Street New York and won, yet few people today know who he was. Philo Farnsworth invented electronic television, yet the history books have us believing RCA was the inventor or co-inventor. Part one: Part two:

Further reading: PDF



Unfortunately, now the powerful Sony Corporation is in decline. It is sad to see that Sony’s vision was lost after the passing of co-founder Akio Morita, and earlier this year, (February, 2014) Sony announced the end of their Vaio computers and the spinoff of their television business. Sony hired their second CEO to stop the bleeding, but it hasn’t helped. It has been my long belief that to succeed you need to stay aggressive and innovate. Maybe Sony became to big in spite of themselves. Sony did innovate in their early years. Masaru Ibuka, co-founder was an engineering genius and Akio Morita was a marketing and financial genius.image They did things the “SONY WAY” and proved all the naysayers wrong. They brought us outstanding new products we could not even imagine. (Apple is doing the same thing now) The inspiring story behind the Chromatron/Trinitron and the “never give up” attitude, serves as a business model for all. Sony needs to re-examine themselves and return to their core values. I hope it’s not to late.

Will the same thing happen to Apple? Time will tell.

I would like to acknowledge and thank all the contributors to this page.

See the Vintage Micro TV page for additional photos, press clippings and information on the Sony KV 7010U Chromatron.