Another Westinghouse H840CK15

[wkand]

Originally Posted by trinescope

Well I have results and some more problems to overcome. I can get picture and sound. I have no color sync at this point. I need to repair the broken coil plug on the hue control and see if that helps. It seems to have normal signal flow in the chroma section when checking with a scope, it just won't sync up. I can get on both sides of the lock point with the color hold control, so that is likely OK.

Next is the HV supply. I was able to repair the damaged focus pot. I made a new resistance track using thin phenolic board and pencil lead. I applied the pencil lead to the roughed up surface of the phenolic strip until I got the correct resistance value. I then installed it in the potentiometer housing. It seems to hold up even when constantly adjusting the control. I had to replace two doorknob capacitors as well. Now I get 27KV and can't regulate it down to normal. Possibly one of the high value resistors is out of tolerance.

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Eric, you have made unbelievable progress in a very short time. Take a bow!!! You have used a ton of creativity in getting things to work.

Regarding the pots you repaired. How did you get the graphite from the pencil lead to adhere to the phenolic board? You had mentioned using a certain type of glue, but I couldn't find the reference when I reread your notes.

[trinescope]

Originally Posted by wkand

Eric, you have made unbelievable progress in a very short time. Take a bow!!! You have used a ton of creativity in getting things to work.

Regarding the pots you repaired. How did you get the graphite from the pencil lead to adhere to the phenolic board? You had mentioned using a certain type of glue, but I couldn't find the reference when I reread your notes.

Thanks for the kind words. I tried mixing India ink into epoxy but that didn't work, probably because the ink is water based and didn't mix well. Also, the epoxy didn't get hard enough to be able to be used as a resistance track, even without anything added. Next I tried adding ground up pencil lead to lacquer, but that didn't work either. I could have tried getting powdered graphite and adding that to lacquer again, but I didn't want to go through waiting for that to arrive, so I went back with my old idea of pencil lead rubbed onto a suitable surface. I initially used card stock for a trial and got a strip which measured almost exactly 5MEG, but since this part dissipates a bit of heat I didn't feel it was a good idea. That's when I started looking for a thin phenolic sheet. I got one that was .020" thickness and looks like thin PC board material. I roughed up the surface a bit with fine sandpaper and rubbed the pencil on it until I got close to the correct resistance. It really didn't take a whole lot of pencil rubbing to get there, and you could see light through it.