1981ish Zenith System 3

[davet753]

I think RTVNUT is on the right path here. If you don't have a cap checker, you can bridge a cap across the filter momentarily and see if that corrects the problem. Those sets are at an age where the filter capacitors are likely starting to go down.

[zeno]

Filter caps common on both 9-160 & 9-181 sets. Caps
usually have lots of puss coming out & you can see it from
the top. It will be the biggest cap on the bottom board.
It may be a hoz or pin problem also.

For model # look on CRT for little tear off labels and on the
plastic frame & inside cabinet. The 9-*** module numbers
actually can help more...............

73 Zeno