[bandersen]

I understand and appreciate the suggestion. I really want to figure this out. Check out the schematic. For example, the HV box gets both the filament power and common reference for the DC power from the hot side of the AC line. They intentionally tie the filament and cathode together on that 12SN7. I've swapped out every single tube and the CRT so I'm think and H-K short is unlikely. Also they problem has also been there before I did any work. I powered it up on all the original parts and was able to get an image and it had ripple.