VAX 4000-500 PSU Overload?
dave.g4ugm at gmail.com
Sat Dec 19 14:44:07 CST 2015
> -----Original Message-----
> From: cctalk [mailto:cctalk-bounces at classiccmp.org] On Behalf Of Robert
> Sent: 19 December 2015 19:19
> To: 'General Discussion: On-Topic and Off-Topic Posts'
> <cctalk at classiccmp.org>
> Subject: RE: VAX 4000-500 PSU Overload?
> > -----Original Message-----
> > From: cctalk [mailto:cctalk-bounces at classiccmp.org] On Behalf Of Dave
> > Wade
> > Sent: 19 December 2015 18:32
> > To: 'General Discussion: On-Topic and Off-Topic Posts'
> > Subject: RE: VAX 4000-500 PSU Overload?
> > Seeing as it already seems to have over current sensing, I guess it
> > has
> > small resistors in there so perhaps it is possible to measure the
> > notices one looks like this:-
> > http://uk.farnell.com/welwyn/oar1-r020fi/resistor-1-0r020/dp/1200359
> Ah! So that is what those things are! I definitely think this one is
> something wrong and shutting down the 12V side. I have just been doing
> some tests with a dummy load and the 12V side will come up and then go
> down a few moments later, sometimes it will stay up, it seems a bit
I wonder if the voltage level detection thinks its out of spec, rather than
the over current parts. These PSUs afre exceedingly complex...
> Presumably then, there is something wrong with the overcurrent detection.
> I will have to look into how you test these, or perhaps just replace them
> see what happens.
I can't see the resistors themselves being the problem. Perhaps re-soldering
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