I'm planning to replace capacitors C50 and C51 first. Actually, they're both in a combined "can." I've noticed that seemed to be common in the 1950's and 60's, where two or more electrolytic filter capacitors were put together in one unit. I guess it was just to save space. According to the schematic, C50 and C51 are connected to a 5U4G rectifier tube. There's a loud hum and buzzing on the speaker that doesn't respond to the volume control. That's exactly the same behavior I've noticed on antique tube radios when the filter capacitors are bad. On my radios, as soon as I replaced the caps, that always fixed the problem. So that's why I'm suspecting that the filter caps are the main problem with the tv. It sounds like the same loud buzzing from the AC line. I know it might not be the only problem, but I sure hope it's the only major one!
There's also another capacitor in that "can," C15. (On page 110). So in total I'm going to have to replace 3 capacitors when I take out that one unit. I really wish they hadn't put capacitors together like that! I understand they probably did it to save cost and space, but it makes things a royal pain now!
I'm attaching a few pictures. I have the tv taken apart right now. Believe it or not, the chassis looks a lot better than when I first got the tv! It was completely covered in dirt and dust before!
I tried to get a picture of the screen with the tv on. There are flickering horizontal lines, which hopefully you can see in the picture. It looks brighter than in the picture though. The fact that the lines look fairly clear even in the daytime and the screen does respond to the brightness control is hopefully a good sign that the tube is still good. I'm suspecting that the wild flickering is caused by bad filter capacitors (C50 and C51). Since that supplies DC power to everything else, I would think that AC rippling would cause problems everywhere.
This is the biggest repair project I've ever done, so I'm just going to have to take this a little at a time!
- Chris