Hi.
I have a C1-93 in a very good overall shape, but it needs a re-set on its compensation trimmer capacitor set. I need a real service manual (not the only available containing the schematic only) to how and in wich order it has to be set with what signal. Basically I know the goal and I can figure out at wich divider wich pairs should be trimmed, but an official solution would be more convenient.
Symptom is in Ch1, 1V range (and only that one, anything over and above it is OK) starts to roll off signal at around 5 kHz and goes to almost half value around 300 kHz and after it stays there. square wave is also very bad at 5 kHz. Trimming C6 cures this frequency dependent division, but of course at the expense of the squareness of more ranges.