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psu question??

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-=HN=- Wild9

Member
Joined
Sep 10, 2001
Location
Dayton, Ohio
If i had a bad motherboard would the psu still power up the fans connected via 4 pin molex connectors? or would nothing power up at all?
 
does the power button connect straight to the powersupply? i dont know if they make these anymore but those things you can plug into power with nothing connected at all and they will start up...cant say ive seen a PSU that turns on through the motherboard work with a broken motherboard, but then again your ram or processor could be the cause of mobo looking broken too. i hate it when this happens!
 
well a person i know was having a computer problem, of course it was his daughters Barbie computer, i checked it out and i could not get anything to turn on, it was really hard to work with it too since it was like a baby micro atx mobo(specially made for those hot wheels and barbie comps) everything was USB no serial ports, no ps2, nothing!, i diagnosed it as a bad psu, he took it to comp usa and they said it was a bad mobo. so i was not really sure if a psu would still powerup if plugged into a bad mobo.
 
-=HN=- Wild9 said:
it was like a baby micro atx mobo(specially made for those hot wheels and barbie comps)

Not exactly the proper test subject...heh
 
oh it was a real computer just different from most others that you see, it had a modem , a place for a printer, RAM, a celeron 600 cpu 6 gig hd, lets just say it took me 30 mins to get the case open...
 
Does the mobo have a light showing that the motherboard is getting power from the PSU, there was a PSU method where u take something jab it in and you'll see some power showing the PSU would be good or not.
 
A motherboard is a complicated piece of electronics. Depending on how it failed it can behave in many ways. Some will do nothing, no fans, no beeps, no nothing. Some will not boot, but will have fans run. Some will even POST, but then hang on the OS load. A bad PSU will can also do some strange things, but that is rare. I have seen them where the fans run, so we replaced, one at a time, the motherboard the memory and the processor. Fans would spin, but no video signal until we replaced the power supply.
The best way to test things is to try them on a different computer or replace them with known good parts.
 
You can bridge the +5v standby wire to the ATX_POW_ON lead to turn on the power supply without the motherboard entirely. This will tell you if the PSU is working at all or not....but not if it's working properly. KD Computers (and others) sell Antec power supply testers that you plug into the ATX connector and they bridge the +5VSB to the ATX_POW_ON lead, apply a 1 amp load to the +5vdc leg to make the PSU stable AND have a little green LED hooked up to the POWER_GOOD lead that will light if the PSU is working.
 
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