1976: 19” Zenith Chromacolor II (chassis 19HC48)

[zeno]

That is often seen with cross hatch. Try backing off the brite, contrast
& sharpness. There are also 1 or 2 more video controls. One on
the 9-88 & another low on the chassis in SOME models.
On the 150-190 IF marked C-2 adust. Try bumping them but remember where they were.

Zeno