Re: Help with Tektronixs 492 S.A. PSU fault.


cricri
 

Hi ,

Open the PSU and test the fuses  !  ( 2 or 3 don't remember )

Seen a similar pb and it was a fuse broken ..


73

F1VL


Le 15/01/2021 à 19:55, Nick Gregory G0HIK via groups.io a écrit :
I came to switching on one time and it light up, but nothing on the display.

The +15 v rail is 4.7v
The -15 v rail is -3.1v.

I think the minus rail uses the plus rail as a reference so it may well be just the + 15v rail faulty.

I've disconnected all cards and connectors and the volts are still low, so I dont think is a card fault and it's probably a PSU fault. The 0.3 ohm resistor in the +15v line says its has a draw of 1.0 amps with seems a lot at 4 volts though.

the +/- 17v rails that feed the +/- 15v are fine.

I would have suspected s/c Tants, but there does not seem to be any tants.

Any help welcomed please.

I've included a part of the circuit with some voltages on.

Thanks Nick G0HIK


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