Another Predicta thread

[Down Under]

Originally Posted by Electronic M

Could be 50Hz leakage from a tube with a H-K short...

Hmmm... I think Iv'e swapped out all the tubes, but I can check anyway with some NOS tunes I have ready for just such an emergency...

Thanks for the tip!

[DaveWM]

glad you did a video, I would say that is not a HK or any hum related type problem. make sure the yoke pins are clean, the vert height pot is clean, I assume you have replaced the boost cap and all the film caps in the vert circuit.
vert lin pot and bypass cap. oh and let not forget the tube pins, nice and clean.

looks like there is a very subtle flux in the output (not freq) of the vert out tube. somewhat random looking, the last thing I would do is look at the integrators. Or just let it run and see if it clears up on its own.

for hum, ground problems,beat freq problems you would expect to see a very consistant and smooth movement that is precisely timed.