CONTINUING FROM PART ONE

UPDATE, AUGUST 19, 2019, DAY 380, 2019.

Last edited, September 7, 2019.

“Cooking process underway”

Author: The “cooking” process started and the first skeletons appear …

From Mike:

“Hi Marshall.  I have been running the set from time to time when I am in the shop.  Tonight I noticed that one of the damper tubes had no filament. The tube tested fine so the issue is either a bad socket or connection somewhere.  The set has qty 2 damper tubes in parallel and it will work with only a single tube but it was designed with both in order to handle the current in the flyback properly.  Glad I saw this.  Not a show stopper, just another “skeleton”  that I am glad I found.

More later,  

OK, there was in issue with one of the damper tube filaments going dead. The problem is the way the ground takes place on the socket. The method is standard design and the problem is from age and poor soldering techniques during production.  Pin 8  (filament) of both of the damper tubes are grounded by virtue of a  rivet and solder connection at the mounting point of the socket. This method works fine for a while, usually through the “warranty period”.  LOL.  Then, the electrolytic action caused by the difference between the two metals causes some corrosion. As long as the solder connection between the two is good then everything is fine. But that was not what was happening in this case. The parts were not cleaned well enough and the corrosion, even though a small amount, was enough to cause enough resistance to keep the filament current from flowing.  So, the fix is to install a wire from pin 8 of each of those tubes to ground and soldered well at both ends. This fixes the problem forever.  

Pix #1 Pin 8 and the rivet in the center of the shot. You can see the poor soldering job and the circle around the rivet proves that the solder did not flow properly.
Pix #2 The other damper tube pin 8 soldering job also doomed to fail. 
Pix #3 The repair. The black wire connected to both pin 8’s and terminated to the chassis at a good solder point. 

Stay tuned. Mike.”

UPDATE, AUGUST 27, 2019, DAY 388

From Mike: “Greetings Marshall.  After spending a few nights doing some modifications to the convergence circuits I am now claiming that it is as good as it will ever be.  You might recall that the Vertical Dynamic Convergence transformer that we purchased is not a direct replacement for either the CT100 or the Westy, but an averaged value to satisfy both. The blue near the top continues to be a problem but it is better than when I started. I will get a screen shot to you soon.  On another note, I need to order another set of H.V. rectifier tubes to try because the high voltage seems to drop a bit after the set runs for  a while, like 20 minutes.  It starts out fine but drops to 18 KV or so after a good warmup.  These tubes are 1B3’s  and it is a set of 3. I replaced them with a matched set of Mil Spec type early in the restoration process. Then there were a series of issues with arcing that I had to deal with so what I am hoping is that perhaps one of them suffered some damage during those times of arcing.  I won’t know until I try new ones. I have ordered them but was unable to find Mil Spec types,,  Just New Old Stock.  Stay tuned!  

Regards,  Mike”

UPDATE, SEPTEMBER 2, 2019, DAY 394

From Mike: “Hi Marshall.  I am working on other small things while I am waiting for the new HV rectifier tubes.  So, here are the images of my repair for the tone control knob.  I believe that you have the volume/on/off and channel select knobs and they have been re-plated.  Question:  Are these knobs that I have here which are white in color supposed to be gold in color?  This tone control knob looks like it was gold at one time.  If so, I can shoot them with some paint to make them match.  Let me know if you learn anything about that.  

Photo #1  First step.  Re-attaching the broken piece to the main part using JB Weld epoxy
Photo #2  The first “real” layer of epoxy over the repair.
Photo #3  I used electronic lacing tape (very strong stuff) ,  tightly tied around the previously broken part for added strength. Then added a second layer of epoxy.
Photo #4  Finished and ready to re-install the circular spring.  Not real pretty, but likely won’t break again.  And nobody sees this part.

The other white knob is for fine tuning and they will both be cleaned with a solution of dish soap and water using a small brush. There are two other knobs which are plastic and gold in color and may need polishing.  I will be careful if I attempt to do so.  

West 32 coming soon. Mike.”

UPDATE, SEPTEMBER 3, 2019, DAY 395

I have been doing detail work.  The 300 ohm twinlead that connects the tuner to the back cover was in very bad condition.  I have replaced it and given it a path up and away from the chassis.  This keeps frequency coupling issues to a minimum.  Once again, I used electronic lacing tape to provide the strain relief.  Also, a screen shot of the convergence.  Still waiting for the new HV tubes. I believe they should arrive on Wednesday.  I am a bit concerned with the lack of contrast at times. I will be replacing the video detector diode in the next report.  This diode is buried inside a copper can.  

Pix #1 The new 300 ohm twinlead path.
Pix #2  The screenshot of the convergence. Still issues with the blue. 

Cheers,  Mike 

UPDATE, SEPTEMBER 5, 2019, Day 397

From Mike” “Upon receiving and installing the new H.V. rectifier tubes, the High Voltage is now, once again, very stable at all brightness levels. YAY.  And I have installed  mesh screen where the panel was missing on the side of the cage.  I could not get a good image of it due to the meshwork.  Not sure why.  And, I am still not happy with the contrast levels, especially when operating from DVD. The images with antenna TV are mostly acceptable but the contrast control is always rotated all the way up. I would like to get a bit more video drive out of this set if possible.  I have decided to go in to the sealed copper can where the video detector diode is, and replace it.

Pix #1 and pix #2 After removing a copper shield on the bottom of the chassis, and disconnecting 2 wires, some screws and desoldering, the can is removed from the chassis.
Pix #3  The video detector diode from 1954.
Pix #4  The new “all glass” version from 2019.

Pix #5  The can re-soldered, sealed.
Pix #6 and pix #7  Re-soldering to chassis.
Pix #8  Re-solder 2 wires on bottom of chassis.

Pix #9  Resoldering the shield/cover on the bottom of the chassis.  
Pix #10  Screen shot

Although I feel very good about replacing the video detector diode, since they can be problematic,  only a slight increase in contrast has been gained.  I will be taking yet another look at what I might be able to do within the video amplifiers in an effort to squeeze a  little more contrast out of the set. The photo of the screenshot show up  much better then they really are.”

UPDATE, SEPTEMBER 6, 2019, DAY 398

From Mike: “Greetings.   In the process of making adjustments in the horizontal oscillator, the trimmer capacitor shorted out.  Glad I went through this procedure.  I replaced the original mica capacitors with a silver mica fixed value type and a small “air variable”.  This worked very well.  

Pix #1 Drilling out the rivet that holds the original assembly.
Pix #2  The old failed cap on the left and the new components on the right.
Pix #3  The new parts mounted on a terminal strip.  

West 35 on its way.

Mike”

UPDATE, SEPTEMBER 7, 2019, DAY 399

From Mike: “We have contrast!  I changed the cathode resistor in the first stage of video (12BY7).  Factory specs calls for 56 ohm.  I tried different values downward in ohms and I arrived at 39 ohms which is roughly half the original value. The contrast improved by about 20 % and it did not affect the high frequency response of the amplifier.  I am real happy with this improvement.  This essentially increases the current going through the tube.  Not to worry, we are still way within the specs of the tube, and the contrast control is no longer all the way to its maximum position. We now have “room to spare”.  

Pix #1  Oz 1
Pix #2  Oz 2 

Enjoy!

I think we are now in the “cooking stage”.  

Mike”

Author: Mike nailed it! Much improved from the previous screenshot. The colors are well balanced. Color, gray scale, geometry, focus and convergence are very good in this viewers opinion. I think this will be the last update for now, unless something comes up. We have to be concerned in transporting the monster chassis’s and CRT. Mike has to travel 12 miles on a dirt road from his ranch. SLOW is the key word. Can’t wait for this set to arrive home to me. Our restored cabinet is waiting. 🙂

SEPTEMBER 13, 2019

Mike said to expect delivery of the Westy in October, so in the meantime, we placed the 15GP22 and chassis’s in virtual cabinets. 😁

Back to Westinghouse H840CK15 Color TV