Could this be anything other than a faulty PSU - and how to prove it

Jetway MA3-79GDG combo motherboard
Phenom II x3 720
2x2gb DDR3
Galaxy GTX260 896mb
Tagan 500w PSU
500gb SATA
4x8cm fans
Vista 32bit
Not overclocked.

My PC is shutting down at random moments, sometimes not letting me turn back on for 5/10 mins, sometimes letting me turn on straight away, and sometimes erasing the CMOS.

I checked the voltages with a multimeter and they seem to be OK (but this is when the PC is working, so this would not show low voltages causing the shut downs)

When it is not shutting down everything is working fine.

The wiring is fine, every connector is perfectly in place - power comes straight from the wall.

From reading my A+ book, this sounds so much like an intermitent PSU fault, and I should replace the PSU.

But, the store has already said the PSU is fine (because it worked for 5mins in their store) without sitting in their store for 5 hours waiting for a shut down, is there anyway to prove the PSU is faulty?

I will replace the PSU, but I would prefer to get a refund on the current (3 weeks old) PSU, rather than pay with my own money.
7 answers Last reply
More about could faulty prove
  1. Have you checked your system and CPU temperatures? If something happens to be running hot, it may trip over its limit setting and shut down then force a delay to cool before it re-starts.
  2. hmm Tagan is kinda of an unknown brand to me, anyone got experience with them?
  3. Erasing the CMOS? That doesn't sound like a psu problem. Looks like a motherboard problem. Check your temps.
  4. temps are all fine.

    the only reasons I said that the CMOS being erased was due to the PSU, was that my A+ book said that was a symptom of a failing PSU.

    could it be something to do with the electrical supply to my house?

    it is an intermitent problem, so most of the time the voltages are fine - but I have my multimeter connected now, and I will wait to see if there is a huge increase on the 12V next time the PC shuts down.
  5. When do these random shutdowns occur? If they occur primarily when the system is under a heavy graphics load (gaming, for example), you very well could have power problems. Or a video driver problem.

    The problem with monitoring the 12 volt line is that a dropout can also shut the PSU down.
  6. totally random.

    normally when I wake up and start my PC, it takes 2 or 3 presses of the on button to get it started - sometimes it just does not want to know and I have to leave it for 5 mins before I try again.

    sometimes when gaming, sometimes when sitting at idle doing nothing.

    when it shuts down, it is just all power off - no fans, just like pulling the power cable out.

    when it shuts down sometimes it will start again if I press the on button a couple of times, sometimes it makes me wait 5 mins - if I have to wait 5 mins to start the PC again, then half the time the CMOS has been erased.

    The motherboard has an ON button that I can use instead of the case button, this changes nothing.

    Temps are fine - all within safe margins.
    Right now my 12V is sitting at 11.93/4

    The only weird thing that I have not worked out is that in the wall I have two power outlets - 1 is purely for the PC, 1 is for a multisocket that powers my monitors/speakers/usb HDD/etc - when the PC is off and I set up the multimeter I get a high reading - even if the PC is not plugged in, but as soon as I disconnect the multisocket from the wall outlet, the volts go down to zero. How could it be showing voltage when there is no power cable? Is it somehow drawing power from the monitor? speakers? this confused me plenty.
  7. *** ed on your machine.

    That can cause random issues..... maybe unplug the case wires and then use the onboard buttons if you have them, if not short the power up pins on the PSU (or just the connectors them selves on the mobo)


    what i meant to say is check the power AND reset button on ur case and see if they are causing random crap.
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