Quote:
Originally Posted by Electronic M
By waviness do you mean to say that with a digital source after a while the top of the screen starts to flag wave in a similar manner to what it does with a VCR?
If so there are a few things I would do: Change the lytics in the power supply (so we know the B+ rails will be stable) if you have not already done so. Make sure all caps in the AGC, sync separator, Horizontal AFC, Horizontal oscillator, and H output have been changed, and make sure all resistors in those stages are within tolerance, also confirm the tubes in those stages are healthy.
After doing that it may be wise to adjust the AGC after it has warmed up long enough for the sync to have gotten wavy. If the AGC is too high or too low sync may be affected. The AGC pot will have a low no signal zone where the picture fades to white, a good zone where sync is strong, and an overload zone where the pic will go negative and loose sync, and the audio may turn to buzz. Generally you turn up till you hit the overload region then back down just past the point where overload symptoms stop (some service lit for some sets specifies 1/4 turn below overload).
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Yes, very similar. However the wave issue sometimes appears within the middle of the image depending on what is displayed. Also a little bit of wave on the bottom of the screen can occur. When I get some time I'll have to go through and recap those sections. I have currently already done the horizontal and vertical oscillation boards. Its probably just time to do a full recap in sections as all issues seem to be related to them. As for the tubes, I have no way to check those out sadly.