Re: Tek 576 possible power supply failure
Martin,toggle quoted messageShow quoted text
-75 V is the important one that is the main reference supply. In one of the 576's I have rebuild the 5V filter cap was bad and needed to be replaced. Also what version of the rectifier board do you have in one of mine it had sprauge black and red paper and foil caps on the board I had to replace ALL of them. They all measured 100+ Ohms ESR 111 to 119 if I remember correctly. There is also some small electrolytic cans on the regulatory board that needed changing as well. On this unit in question it was a VERY early one gold plated PCB's everyware. With a -00 tube if that dates it at all.
From: TekScopes@groups.io <TekScopes@groups.io> On Behalf Of Martin
Sent: Friday, January 29, 2021 3:44 PM
Subject: Re: [TekScopes] Tek 576 possible power supply failure
Right now it seems the -75V supply is working. I disconnected all 3 loads of the 100V supply and it still does not come on, so I'll concentrate on that.
I was supplying an external voltage into the 100V leads, that seems to do the trick as the 12,5V supplies came to life. The screen looked a bit weird though (not a nice sharp trace, but a stable trace at least). Current draw off the 100V external supply was around 80-90mA.