Well, let's see: I took the bottom off the VT52 and checked the
connections to the high voltage board on the back. Cleaned up both
connectors, plugged in, same problem.
I do hear a medium to high pitched squeal coming from the back board.
Can't quite triangulate it (I need a hose and some time) but it might be
coming from those center transistors. Any idea what these boards are
doing, and if there is a schematic for these circuits?
Given that it went weird after being powered on for awhile I would
suspect it has something to do with a component that generates heat. I
could also take an IR picture of the back board and see if anything is
unusually hot/not hot.
Audio of the noise: https://i.imgur.com/ps4Ovkj.mp4
Pic of the back: https://i.imgur.com/HgNoTYK.jpg
C
