ATX Power Supply, or power switch?

December 29, 2009 at 11:12:18
Specs: Macintosh
Hi guys!

I think my power supply has failed on me. I would like
to believe it was coincidence, but it happened just
hours after modding in new power and reset switches
on my case.

They are toggle switches, but I realize that ATX only
uses momentary contact on the circuit to power on
and off so I just flip the switch back and forth to
remedy this.

Anyway, my computer was working dandy, then it just
shut down without warning and would not power up
again. I would be able to flip the switch and get some
action (fans would spin and light up, including the
CPU fan) but no loading screen.

I know this sounds like power supply failure, but did
my modding practices somehow cause this? these
switches are kind of old and from my dad's shop. It
has some info on the switches themselves regarding
voltage and whatnot;

Power switch: 25 amps, 12VDC
Reset switch: 3A 250V
5A 125V

Thanks so much for your help!


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#1
December 29, 2009 at 12:31:26
See pages on how to start power supplies with a paper clip.

Be careful, or take it to a shop if you feel unsure.

It could be possible that a stuck switch could damage the lan on the motherboard between the ps switch and ps connector.

Test the ps is the first step. Could check the switch with a ohm meter. A momentary would have been better.

Playing to the angels
Les Paul (1915-2009)


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#2
December 29, 2009 at 12:42:59
Why would you use toggle switches for that? Seems like a step backward to me.

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#3
December 29, 2009 at 13:11:03
Well my power supply turns on, i know this, so why would I
need to hot-wire it with a paperclip? What would that reveal?

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Related Solutions

#4
December 29, 2009 at 13:28:33
Disconnect all 4 leads for both those switches and try momentarily shorting out the two power switch pins using a flat blade screwdriver. That will eliminate the new switches from the equation.

Be aware that a PSU can partially fail and appear to be working.


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#5
December 29, 2009 at 16:13:38
Ok I did the screwdriver trick and I get the same results
(powers on, but not really). So I've pretty much confirmed my
PSU is damaged. However, was the cause of damaging my
PSU the new switch? What would I need to look for if I was
measuring with an ohm meter? I guess I would like to know if i need to get another PSU whether or not I need to put my old switches in too.

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#6
December 29, 2009 at 17:08:23
Verify that all the PSU to board connections are made up and solid. The 20+4 pin power connector, the 12V direct to motherboard, any power connectors to your graphics card. Also re-seat all card, cables and RAM. When inside the case you may have disturbed something.

I would still like to know why you changed the switches.


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#7
December 30, 2009 at 08:53:52
If you looked up the pages I suggested you would have been able to decide. There must be 300 pages devoted to this on the web already.Mean ain't I?

Playing to the angels
Les Paul (1915-2009)


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#8
January 3, 2010 at 21:54:54
Ya, I've pretty much confirmed a dud power supply, but I'm
taking it to a shop to make sure. Hopefully it didn't damage any other components. Thanks for your help.

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#9
January 13, 2010 at 14:57:48
So the official diagnostic was a dead motherboard. I must
have shorted something pretty serious, because the
technician couldn't even get it to POST. He tested the
voltages of the power supply and they were normal.

New motherboard (and case) it is. Hope this helps someone.
Also the ATI graphics card's 3 red lights are potentially
caused by the motherboard as well, not even involving either
the power supply OR graphics card.

And OtheHill, I changed the switches because my case
sucks. I couldn't put anything in the 5 1/4 drive bays
besides DVD drives (they have that flip-open tray deal) and I
wanted to put a fan controller in. I am going to get a full-
tower case with an EATX mobo. My old system was mATX
(much too small).


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