[OldTechFan96]

I replaced C408 with a similar component that I had knocking around.

After two and a half hours turned on the fault conditions appeared. The voltages at TR403 stayed the same.

When I touch my finger to the tip of the probe I can make the scope show a waveform that slowly moves across the screen. I imagine that adjusting the trigger controls should cause the wavevorm to lock so that it is stable. No amount of adjusting gets the waveform to lock.

Tomorrow I will lift R426 and let the scope run for a few hours to see if the trace disappears.