19 Dec
2015
19 Dec
'15
9:19 a.m.
-----Original Message-----
From: cctalk [mailto:cctalk-bounces at classiccmp.org] On Behalf Of Mouse
Sent: 19 December 2015 16:09
To: cctalk at classiccmp.org
Subject: Re: VAX 4000-500 PSU Overload?
good
But getting something in series to measure load
is going to be really
awkward, [...]
As in, you don't have any such thing to put in series, or you don't see a
way to get it in series? I've got a couple of 0R1
resistors which work
nicely for
that in conjunction with a voltmeter that can handle
millivolt
measurements;
you might be able to get something similar. Mine are
10W, and, while they
are designed for bolting to a heatsink, they can probably handle at least
2 or 3
watts, which means some 5-6 amps, in free air.
(Though that then drops
about half a volt, which can be a problem when you can't put it on the
input
side of the
regulation.)
I think the suggestion was to put an ammeter between the PSU and the
backplane. That would be awkward to make all the connections with the PSU
out of the machine. Also difficult is to make a dummy load for a bench test
that draws enough current to test that it can sustain its rated output at
full load (or some decent proportion of full load at any rate).
Regards
Rob