VAX 4000-500 PSU Overload?

[Robert Jarratt]

> -----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
some
> small resistors in there so perhaps it is possible to measure the current.
I
> 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
detecting 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 random.
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
and see what happens.

Regards

Rob