Switcher PS temperature...

From: Bill Sudbrink <wh.sudbrink_at_verizon.net>
Date: Thu Jan 13 23:11:40 2005

In the ongoing saga of my OSI C4P-MF that had a PS melt
down at VCF east, I determined that the whole thing, in
operation, draws 7.2 amps at 5 volts. The two stock 5V
supplies are rated for 3 amps each. They are obviously
being over stressed. I can't point my finger at any
particular "bad" component... everything seems to work
just fine when given sufficient current and nothing seems
to be drawing more than a few percent out of spec.

Anyway, being tired of running it belly up with a large
fan blowing on the PSs, I identified a small switcher
that would nicely fit in some spare space near the
original supplies. You can't actually remove the original
supplies, their frames are integral to the structure of
the machine. The supply is a Power-One MAP42-1005 available
used (and cheap) from WeirdStuff (note URL broken across lines):


spec sheet here:


It's rated for 8 amps with no significant airflow (if I
understand the specs correctly) so, I'm not even pushing
it to its limit. Anyway, after about 10 minutes of
operation with the case open and the new PS sitting off
to one side (clear all around), the two heat sinks are too
hot to touch. Is that normal operation for this kind of
supply? Maybe I got a bad one from WeirdStuff? Or
could this be some additional clue as to something wrong
somewhere else in the computer? According to my meter,
the voltage is spot on 5 volts and the current is 7.2 amps.
Any suggestions appreciated.
Received on Thu Jan 13 2005 - 23:11:40 GMT

This archive was generated by hypermail 2.3.0 : Fri Oct 10 2014 - 23:37:44 BST