Weird Problem - not sure if it' PSU or Mobo-related.

trjp

Active Member
Was asked to fix a 'dead' PC about 2 weeks ago. When I got it, it powered-up AOK and I was wondering what 'dead' meant when it decided to instantly power-off again.

I took everything out and tried each bit in turn - but it was only when I replaced the PSU (with an old spare) that it powered-up again.

So I sourced a new PSU and all seemed well - so it went back to it's owner.

Within 2 days of getting it back, it reverted to it's old tricks - shutting-down instantly after about 10 mins of use. It will not power-on again for quite some time afterwards.

It does this even in the BIOS screen so it's nothing to do with Windows. It does it even with everything but the Mobo connected to the PSU - so it's not an HDD/DVD or anything like that either.

I've checked (using BIOS and Speedfan) and it's not overheating (temps are <35 degrees when it shuts-down) - tho the PSU could be overheating I suppose..

Weird thing is - both old and new PSU are unstable in other PCs too - which suggests both PSUs have the same fault - which further suggests it's the PC/Mobo which is actually frying the PSUs???

Any other ideas?? - I could get the 'new' PSU swapped as faulty and see if it cooks the next one but other then that - I'm out of ideas and thinking this PC is a toaster??
 

trjp

Active Member
By way of an update, I think I sussed this out.

3 diff. power supplies all failed with this PC - they work AOK in other systems tho.

My conclusion is that the mobo is fried and it's somehow overloading/overheating the PSU. Once it's cooled/reset it seems fine.

Mobo/CPU now in the bin :)
 

amstel78

Novice Member
By way of an update, I think I sussed this out.

3 diff. power supplies all failed with this PC - they work AOK in other systems tho.

My conclusion is that the mobo is fried and it's somehow overloading/overheating the PSU. Once it's cooled/reset it seems fine.

Mobo/CPU now in the bin :)
Just curios.
What kind of brand was the motherboard ?
 

getjpi

Standard Member
By way of an update, I think I sussed this out.

3 diff. power supplies all failed with this PC - they work AOK in other systems tho.

My conclusion is that the mobo is fried and it's somehow overloading/overheating the PSU. Once it's cooled/reset it seems fine.

Mobo/CPU now in the bin :)
I've seen similar before, board powers off when it gets warm. Could be a dry joint/crack somewhere.

Greg
 

semo

Standard Member
If you can get your hands on a voltmeter, you can check the voltages while the PC is running and also monitor whether they drift as the pc gets closer to crashing. Just stick the probes behind the 24-pin connector. Off the top of my head, black is earth, yellow is 12V.
 

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