On Mar 7, 4:18*pm, "J.B. Wood" wrote:
Hello, all. *I have a circa 1991 Zenith Sentry 2 TV model SJ206585 that
still has a great picture but there are diagonal lines (not retrace
lines)
Those are horizontal retrace lines occurring during the vertical
retrace interval. If you can find the 'blanking' adjustment, tweak
it.

If there's no blanking adjustment, it's time to tweak the high
voltage
adjustment called (usually) 'screen'. It's likely that contrast
will get lots better when this is done correctly. Don't let
the shadow detail get lost, though.