Hello, Paul.  Good to see you posting here.
-=> PAUL ROGERS wrote to ALL <=-

 PR> Anybody got any tricks for testing ATX power supplies, without trusting
 PR> one with not frying a motherboard?  What's the best way to test a P/S?

First off,  If DELL has anything to do with it, be _careful_ - - Dell
power supplies and mainboards from 1996 thru about 2000 used proprietary
pinouts for both mainboard and PS.  Hooking either from Dell up to a
"standard" PS or mainboard could well cause damage.

With standard ATX PS pinouts,  one simple check which can be made - with
mains power attached, and PS power switch (if any) turned on,  shorting
between ATX power connector pin 14 (green wire, per std) and either of
the adjacent black ground wires will cause the PS to wake up, and the
fan to start spinning. The whole thing will 'shut down' again when that
short between those pins is released.  I doubt at that stage that there
is a way to do much of any meaningful voltage readings on the other
pins, since there is no load attached to the PS, and its voltages will
not likely be stabilized to near what they might be if PS were
connected to a MB.

There are devices made and sold which purport to be an "ATX Power Supply
Tester."   I haven't used any of these, and do not know how valuable
their apparent test results may be wrt any kind of "real PS testing",
which I tend to think would need to be done with loads attached which
were reasonable approximations of what might be required when the PS is
attached to a "real" mainboard,  drives, and etc.

There is a writeup at Tomshardware -  at

www.tomshardware.com/column/20011012/

in which he describes using one of these PS testers, and it shows a
picture of one.  In the article, he just used the PS tester to confirm
what he really already knew - - that a new 'el-cheapo' power supply had
just died on him in a cloud of smelly smoke.  The article was IMO more
interesting in what he had to say about the inferiority of the
"el-cheapo" PS units are out there today.

Anyway, a Google search on "ATX Power Supply Tester" will find a _lot_
of hits.  PS makers like PowMax,  Antec, and PC Power and Cooling
offer such testers at their websites, and elsewhere.  Most seem to
include at least one loading resistor, which is purported to stabilize
the voltages from the PS.  Some mention having test points for attaching
a voltmeter and testing voltages.  The one by PowMax may test more
things than some others, since it seems to include more LEDS and
indicates that it tests for more voltages, even including the PWR_Good
signal.  These testers start at under $15.  Again, I have no experience
with these, and don't know how valuable their results may be.

We have an ATX test bed where I volunteer, with known good components,
and that is where we would normally "test" ATX power supplies. (After
making sure that they aren't those '96-'2000 Dell things).  We hook them
up, and if the system boots, we presume the PS's to be good.

What I'd like to have for ATX PS testing is a box with multi-lightbulbs,
and pin points for reading voltages, which would test all of the various
voltages at one time, during reasonable power loadings.  But - I've
never seen such a tester offered for sale.

I'm hoping this response will spur some more replies.

Good luck.  - - -  JimH.


... "Bother!" said Pooh, as he saw the sparks and smelled the smoke.
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