*sigh* ATX PSU problems...

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Obviously I'm missing some vital piece of information regarding ATX PSU's...

Today I shut down two PC's. Turned off the PSU switch at the back. Removed
an internal USB card reader from PC1 and installed it into PC2.

At this point I flipped the switch on the PSU of PC1, then hit the power
button on the front. Nothing... nada... I looked and the switch is in the
"1" position. Flick it off and on, push the power button up front. Nope...
still nothing. BAH! Checked all cables, plugs, cards and everything is snug.
I pull all the case wiring. I push the Power button on the mainboard (DFI
Lanparty, has onboard power & reset switches) and still nothing. "GREAT! I
just killed the PSU and don't know how." So I put the case wiring back in,
still no go. I hit the RESET button, nothing , power again, nothing... THEN
I push the Power and Reset button at the same time and I hear a faint click.
Pushed the power button and the PC starts up fine. No issues at all.

Cursing I go to PC2... Flip the switch on the PSU on, hit the power button
up front... NOTHING! Goddammit! This is a 450watt FSP PSU running an Asus
P4C800E-Dlx mainboard. I swapped the Power and Reset button case wiring, try
reset, nothing. Hold both buttons hoping to have the same luck as before,
nothing. Cleared the CMOS with the mainboard jumper, nothing.  When the PSU
is switched on, the mainboard power LED is lit.

So. Now my server won't start. BLAH.

WHAT is going on here... This is too much of a coincidence!

Re: *sigh* ATX PSU problems...

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That makes it sound like a flakey motherboard, the need to press both.

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Yeah, what's the detail on the two power supplys brand and model wise ?

Have you checked for bad caps on both motherboards ?

Are the systems normally left on all the time ? If so, the bad
caps may well have developed over time and you only noticed
when you had to turn them off to move the card reader.

Re: *sigh* ATX PSU problems...

On Wed, 13 Dec 2006 18:25:23 GMT, "Noozer"

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I wonder if something was shorting out the first time you
tried it, and so it was a matter of time till the PSU reset.

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I'd wonder if you had too much stuff powered by 5VSB, are
your PS2, and/or USB ports jumpered to that?

 If you have a multimeter, check the battery.  Does this USB
card reader use a plug or a pin socket?  If a socket, are
you sure both boards have the same USB header pinout?  I'd
at least leave that reader disconnected till you revive the
system.  Leave the PSU disconnected from AC for at least 10
minutes, clear CMOS, then plug back into AC.  If nothing
else works, do you have a floppy installed so you could see
if it has a bios problem and is trying to access floppy?  If
you took out the video card and put in a PCI video card you
might see output on the monitor if this is the situation.

Re: *sigh* ATX PSU problems...

Noozer wrote:
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Check the P4C800-E Southbridge chip for burn marks. You may have
had a latchup failure of the Southbridge. The ICH5/ICH5R has a
problem, and it seems to be related to static electricity and
USB ports.


Re: *sigh* ATX PSU problems...

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And to add insult to injury. I went back to PC2 after making the original
post and it powered up without any problems.


I'm going to have to check my USB ports and make sure that they aren't
running from the 5v standby as Kony suggested. That's about the only thing
that makes sense here.

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