Re: PSU on a VAXstation 4000 VLC

Robert Jarratt wrote:

"Robert Jarratt" <nospam@xxxxxxx> wrote in message
news:oyNWi.26150$uH.9846@xxxxxxxxxxxxxxxxxxxxxxx
I think I have a faulty PSU on one of my VLCs. After a while of operation
the machine will fail and reboot and then it gets into a reboot-stop-reboot
cycle that does not even get past the memory test. When I came to it this
evening the PSU was cycling on and off at about 1-second intervals, the PSU
fans would just start to move and then stop again, and there is a high
frequency "blip" that goes in time with the power cycling on and off.

Is this a dead PSU or might it be repairable? I have no real electronics
experience, but I do have a soldering iron and I am aware that PSUs are
especially dangerous to mess with.

Thanks

Rob


Further info. If I leave the PSU powered off for a while (just tried for 30
minutes or so) it powers up normally, but there is a high-pitched whine
coming from the PSU. When it was constantly cycling on and off I found that
switching it off and on again immediately did not stop the on/off behaviour.

Hhmmm... Sounds like it may be a fan issue. The fan may eventrually stop,
causing the system to overheat and begin to misbehave.

Just a thought...

--
David J Dachtera
dba DJE Systems
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