1954 Philco high b+ issue.....

[DaveWM]

if its keyed agc, look for a .1ish cap that filters the AGC, again a scope works well here, I generally will scope the AGC after the filter to make sure there is no hash on it. If you do not have a scope and suspect AGC you can just clamp it with a variable DC power supply. With out the correct equipment (scope, vtvm) you can try feeding a composite video signal into the grid of the video amp (pull an IF tube out) and see if you get a good clean pic and video. If you go this route just make sure the chassis is not hot and isolate DC with a cap (a .1 is plenty) when connecting the comp video up. You can get a comp video from most DVD players. Sometimes it will no work due to phase differences but most of the time it works. It may not be strong enough but will tell if the sync is prob is before or after the video detector.