Another Westinghouse H840CK15

[etype2]

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.

Last on the list is the vertical convergence transformer. The reproduction parts are no longer available so I will have to rewind it myself at some point. For now I have wired around it for testing. Of course the convergence is off, but at least I can see how the rest of the set is working.

The CRT may be weak or the kind of picture I'm getting is a result of the excessive HV. It's better than a completely dud tube at least.

Did you contact John Folsom? He may have a VCT. SEE THE BOTTOM OF THIS LINK: http://www.videokarma.org/showthread...=270450&page=5

[trinescope]

Yep, already tried emailing John Folsom, he replied that he has no more transformers available. The one in my set has either shorts or leakage from secondary to either ground or the primary. This one doesn't look fun to take apart or rebuild. Lots of varnish and many thousands of turns of fine gauge wire. I probably won't get an exact turn count out of this. Also looks like the laminations are stacked in alternating directions, so they'd have to be pried off one by one.

[kvflyer]

Sure is nice to see what certainly appears to be a good CRT! Major obstacle overcome. Thanks for sharing your progress and pictures.

[trinescope]

The apparently weak CRT turned out to be a wiring error on my part in the color video amplifier section. I had a coupling capacitor essentially shorting blue and green signals together as well as shunting the green signal to ground. Correcting that as well as going through a few adjustments in the chrome section allowed me to get a color picture at last. The set still does not like displaying very bright scenes, but these sets probably never got really bright pictures to begin with, so I will just keep the brightness down. Color lock is still a bit weak. Still need to come up with a solution for the vertical convergence transformer to get this working like it's supposed to.