MS9-29 Powers up but then HV shutdown

[Velyks]

Hi!
I'm trying to resurrect a clean-but-not-working MS9-29. This is my first time doing chassis repair.
The symptoms are:

1. Powers up fine, B+ around 76v, but with no picture. I can feel HV on the screen
2. 30~ secs later something clicks and B+ goes to 110v (input voltage) and steadily trickles down. Can't feel HV on the screen anymore. My guess is something is causing HV shutdown.

I have already replaced all the caps as a precautionary measure.
Any ideas or pointers on what to try?

 

[FakeNoose]

I wish someone had an answer for you I could use the help as well, mine almost does the same thing. However, all I get is the initial static, a whine, and then shutdown followed by a chirp a few minutes later.