JIM HOLSONBACK wrote in a message to PAUL ROGERS:



 JH> With standard ATX PS pinouts,  one simple check which can be made 
 JH> - with mains power attached, and PS power switch (if any) turned 
 JH> on, shorting between ATX power connector pin 14 (green wire, per 
 JH> std) and either of the adjacent black ground wires will cause the 
 JH> PS to wake up, and the fan to start spinning. The whole thing will 
 JH> 'shut down' again when that short between those pins is released.

Hmm.

 JH> I doubt at that stage that there is a way to do much of any 
 JH> meaningful voltage readings on the other pins, since there is no 
 JH> load attached to the PS, and its voltages will not likely be 
 JH> stabilized to near what they might be if PS were connected to a MB.

The supply doesn't get "upset" at not having a load connected to it?

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

 JH> There is a writeup at Tomshardware -  at

 JH> www.tomshardware.com/column/20011012/

I appreciate that URL as I've been meaning to hit that site,  didn't have
it handy anywhere.  (Wrote it down as that transfer I'm in the middle of
crashes enough without making things even more complicated...)

 JH> in which he describes using one of these PS testers, and it shows 
 JH> a picture of one.  In the article, he just used the PS tester to 
 JH> confirm what he really already knew - - that a new 'el-cheapo' 
 JH> power supply had just died on him in a cloud of smelly smoke.

Uh oh.  You know what they say about when the smoke gets out...   :-)

Got one of those here,  the one ATX supply not in use.  From what I can see
in it,  one of the filter coils got kinda hot,  which suggests that the
diode attached to that point is probably shot.  One of these days...

 JH> The article was IMO more interesting in what he had to say about 
 JH> the inferiority of the "el-cheapo" PS units are out there today.

 JH> Anyway, a Google search on "ATX Power Supply Tester" will find a 
 JH> _lot_ of hits.  PS makers like PowMax,  Antec, and PC Power and 
 JH> Cooling offer such testers at their websites, and elsewhere.  Most 
 JH> seem to include at least one loading resistor, which is purported 
 JH> to stabilize the voltages from the PS.

One would think you'd have to have at least one.  Presumably on the +5, 
since that's where most of these power supplies regulate?  I think the rest
are all tied to that one...

 JH> Some mention having test points for attaching a voltmeter and 
 JH> testing voltages.

That'd be handy.

 JH> The one by PowMax may test more things than some others, since it 
 JH> seems to include more LEDS and indicates that it tests for more 
 JH> voltages, even including the PWR_Good signal.  These testers start 
 JH> at under $15.  Again, I have no experience with these, and don't 
 JH> know how valuable their results may be.

That was the other thing I was wondering about,  what the prices were like.
 That ain't too bad,  $15...

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

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

It doesn't seem to me that it'd be that hard to build something of the
sort,  once you arrived at some kind of a figure as to what constitutes a
reasonable load on the various voltages.  Do you have some numbers you'd
plug into that?

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

Here ya go.  :-)

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

I hate it when that happens!

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