> -----Original Message----- > From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Robert > Jarratt > Sent: 19 December 2015 19:19 > To: 'General Discussion: On-Topic and Off-Topic Posts' > <cctalk@classiccmp.org> > Subject: RE: VAX 4000-500 PSU Overload? > > > > > -----Original Message----- > > From: cctalk [mailto:cctalk-boun...@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.
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 and > see what happens. > I can't see the resistors themselves being the problem. Perhaps re-soldering them > Regards > > Rob Dave G4UGM
