Great, my VT52 is shot.

Chris Zach cz at
Sat Apr 18 17:56:09 CDT 2020

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:
Pic of the back:


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