Quote:
Originally Posted by andy
Before you do anything, you need to replace all the paper and electrolytic capacitors. Then you can at least safely turn it on and see what you have to work with. A lot of 50's TVs work fine after replacing the caps, cleaning the tuner and other controls, and making a few minor adjustments. Be prepared to find other problems though.
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This is one thing I have learned is very important...if there are any old capacitors still in there it can cause all kinds of hard to track down problems and make it impossible to repair.
I always start with all new capacitors and check the tubes and then troubleshoot any problems which may be due to resistors, etc.
I also highly recommend the photofact. This comes in very handy on sets which use the old color band caps...it helps to confirm which cap is what value. Also you will need the voltage test readings to help you if you have any problems after the capacitors are replaced.
Also just looking at different photofact schematics and tracing how the signal flows from one part of the set to the next is very helpful in understanding it. The schematics are always layed out so you can see how the signal starts from the antenna terminals and flows through the tuner, to the IF, where the sync signals come off, etc. Also you can see things like how a vertical output tube or audio detector can rely on boost voltage from the horizontal output section, or how an audio output tube can act as a voltage divider and supply plate supply voltage to the IF tubes...things that might not be immediately obvious but can help with tough troubleshooting problems.