Servicing a 1966 Admiral PG919 all vacuum tube b&w television. P2/? Horizontal sweep problems
Trying to discover the failure of the horizontal oscillator. Some adjustment, but the frequency is way low, low enough that sweep drops out at times.
The 8FQ7 is a combination oscillator, and amplifier. The first section generates the oscillation, which is supposed to be near 15,750khz. Then the section section amplifies it and provides drive for the horizontal output stage. The 2nd stage is working .The first is only running at about 12khz. Tube substitutions are not working at all.
Lots of polystyrene caps that can fail in these circuits that can cause this symptom. Could be driften resistors. Gonna try and troubleshoot it the best possible and come to a resolution that allows it to work.