Great, my VT52 is shot.

Wayne Sudol Wayne.Sudol at
Sat Apr 18 18:33:06 CDT 2020

Here's a link to the vt52 maintenance manual. Has testing and service info. Hope it helps.


-----Original Message-----
From: cctalk [mailto:cctalk-bounces at] On Behalf Of Chris Zach via cctalk
Sent: Saturday, April 18, 2020 3:56 PM
Cc: General Discussion: On-Topic and Off-Topic Posts
Subject: Re: Great, my VT52 is shot.

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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