Zenith 25DC56 rolling

[Electronic M]

AGC adjustment typically has a low signal (blank raster/snowy pic) range, a mid range with a sweet spot, and an overload range where sync is lost and or grossly excessive contrast/negative pic occur.

Typically you turn AGC up till synch is lost and or pic contrast becomes overloaded, then back it down until sync stabilizes and contrast is in a reasonable range for it's control....It may be worth tweaking the AGC again to see if it is having an effect.

[zeno]

Never had one of these roll. There are a few small 'lytics on the
main chassis. One was in the AGC. IIRC it caused snow, look
that way first.

73 Zeno
LFOD !