Random shutdown (possible power supply problem?)

[pointy shadow]

Hi there,

This morning my PC randomly decided to switch itself off. I have XP Auto shutdown disabled so if there is a hardware problem it should display a BSOD rather than shut the system down.

I have 2 x 512MB of RAM, P4 3.2Ghz (775) on an ASRock 775VM800 mobo, 3 IDE HDs, 1 SATA HD all powered with a Thermaltake 400w PSU.

My line of thinking is that since there was no BSOD displayed it wont be a memory or CPU problem and is either the mobo or the PSU.

After the shutdown I have to remove the power cable from the PSU a couple of times before the PC will boot so thats flagged up a PSU problem to me.

I ran Sisoft Sandra and the following info is taken from the "Burn in" report:

CPU Voltage 1.33v
+3.3v 3.42v
+5v 5.19v
+12v 11.31v
-12v 0.39v
-5v 1.69v

Are the values for -12 and -5v correct or do they look suspect?

Also, after I turned the PC off this morning it appeared that the chassis (Thermaltake Xaser) was still powered up as the front "Thermaltake" blue logo was lit up but the monitor was flashing as though it was powered off. All this was going on when I couldnt hear my PSU running.

Does anyone have any suggestions as to what they think might be going wrong? Personally I reckon its the PSU but I would appreciate some other input.

Thanks for your help

 

[InvaderGIR]

Could be a faulty motherboard, or faulty PSU. Have you had any power surges lately? They can really mess with your parts...my brother lost all but his CPU to one a few months back...which is why I have a surge protection multitap for the PC

InvG

 

[pointy shadow]

Thanks for your reply.

After I posted the PC decided to shutdown again then about 5 mins later it powered itself back up! I was sitting there going "WTF?" to myself and decided that it has to be the PSU.

I have managed to get a loan of a PSU from a guy I know and so far there has been no reboots and thats about an hour now that the new PSU has been in and fingers crossed all is OK.

If, on the other hand, it does it again then I am lost as to what it can be...

 

[Admiral Huddy]

Does sound like a PSU prob to me.. Try using a multi-meter as follows:

1) Turn PC off but leave plug connected.

2) Take power connector (Molex) and insert black probe into black wire connector.

3) Insert red probe into red wire connector.

4) Set multi-meter to 20volts and turn on PC.

5) Read out should be around +5volts.

6) Turn off PC and repeat process but this time connecting the red probe into the yellow wire.

7) Power PC on again and read the read out should give you around +12volts


Allow for some deviation. For 5volts between +4.8volts and +5.2volts and for 12volts between +11.5volts and 12.6volts.

Anything outside these there is certain to be a problem with the power supply.