I'm troubleshooting an old Heathkit AD-1013 Audio Oscilloscope that's behaving oddly. It's a pretty simple circuit and I have the Assembly Manual, which is very thorough, still I'm such a beginner I can't quite figure out what's happening...
In the attached schematics for the Vertical Amplifier part of the scope, test point 3 (TP3) at the collector of Q107 should be at +130V.
It's connected to the +200V rail (actually +193V) through R115 (15K) which is known good.
TP3 reads +193V, how can that be?
thanks!