Zenith jumpy picture ...

[rwagoner]

I have an old Zenith Advanced System 3 console from about 1990 or so. Picture is still beautiful, so I hate to dump it. Got a Firestick and an HDMI to AV converter to get DirecTV Stream to it ... kind of works but I get the jumpy picture that was fairly well-known with some game consoles (etc).

It seems there used to be a modification that could be made to one of the boards to stop this problem (I remember a tech telling me about it). Does anyone happen to remember what it was and how to do it? Or are there HDMI-AV converters that work better?

Here's an oddity - if I plug the video output from the AV converter to the AV Loop Output video connection (instead of the normal AV video input, leaving the audio cables in the input), the picture doesn't jump (or RARELY does) and the video is MUCH brighter. Actually looks great when I adjust the black level WAY down.If nothing else would it hurt the TV to connect it this way? Anyone known why it is brighter?