You're going to need the service manual w/ schematic, some test equipment like a DMM and perhaps another scope and a bit of patience and determination. These are fixable, but they don't fix themselves. If
commongrounder had the exact same issue and can remember exactly which component it was that failed, that might be a 'silver bullet' sort of answer. Silver bullets are good when you get them, but you usually don't.
Service manual is here if you don't have it:
https://w140.com/tekwiki/images/9/9a/070-3826-00.pdfThe first thing to do is carefully check all of your power supply voltages for voltage and ripple. Given how it failed, it wouldn't be surprising to see bad capacitors in the PSU.
If that's all good, I'd guess that your problem is somewhere in the schematic on p. 159 of the .PDF that I linked, which I've shown here. It is possible that the transistor array that
commongrounder referred to is U197.