Hi, I have an SC502 that I broke while trying to fix it.
I was initially trying to remove the mode select cam to clean it because it was full of gunk, but I ended up bending the golden contacts and had to disassemble the entire scope to fix it.
It appears that disassembling the scope and fixing the gold fingers has introduced a new problem. Alt and Chop modes on my SC502 no longer work properly.
Alt has a fault where the trace times are not 50% split, but rather split randomly. Video here:
https://youtu.be/vQjHu17QHKY The switching waveform is what you'd expect. Sometimes it's high, sometimes it's low. The effect is not very noticeable at higher sweep speeds.
Chop mode is more strange though. There seems to be ringing? Some kind of distortion in the chop signal. The oscillation signal by itself seems fine. I'll include some images.
Not quite sure what happened. I've ruled out the cam switches. Maybe I damaged the chips with ESD while disassembling it? I work in my bedroom so it is possible.