sylvania roundie D01

[DaveWM]

ok check out the keying pulse, that looked good, the video signal to the control grid fo the keying tube looked ok. I really need to see the video composite signal in better detail (not the one right at the AGC tube) and look to see if the sync is getting clipped. the AGC is just WAY too critical. I still suspect its in the sync sep tube since the CRT is not getting cut off, its just the sync that gets lost at anything above just when you go from blank raster to fairly weak pic.

I tried looking at the scope signals around that noise gate transistor, but that was inconclusive, I think I will just pull that transistor out and check it.

I still need to confirm that the AGC pot is acting right, I once had a noise inverter pot that was open so it was not acting like a proper voltage divider. I think this one is ok as it seems to function normally but for the narrow range.

have had some off line discussions with another member here, and the thought is the pot may have some issues that are hard to test for with a ohm reading, but better to test by checking the DC potentials at the center lug.