[Solved]System Restarts instead of shutting dow : PSU or Mobo ?

[Guillaume]

Hi Everyone,

ABIT AV-8 MoBo
Windows XP.
Antec Sonata enclosure.
System configuration stable for 3 years.

A few monthes ago, my system started to behave strangely wrt. power off options :

- a Windows initiated "shut down" will seemingly start ok, but when everything has closed and you'd expect computer to go still, it initiates a complete start up. This would happen about every 3 shutdown requests.
- So after the 'computer restarts instead of shutdown', when I hit the power button in middle of POST to prevent a full boot, it will do it again : shuts down but then restarts. It can do this 2 or 3 times in a row before deciding to shut down for good (this kind of rules out any OS/Software aspect I guess).
- Windows 'Sleep' option will make computer restart instead, 100% of time.
- After any of the above event takes place, at next startup BIOS complains it's in safe mode, so I just open bios and save&exit (all my settings seems to be ok), and it boots ok.
- If I use the PSU switch to turn it down completely for some time, or if I pull the plug, and then switch it back on, I have a very hard time starting it again (like pushing 10-15 times on power button).
- Other than that (ie. without using the PSU switch, and provided I don't hit the 'Safe Mode BIOS' prompt), start ups are always ok.
- All other computer functions are fine.

I strongly suspect these are the consequences of recurrent (~ once a day), house-wide power cuts generated by a faulty cloth dryer, which often took place when the computer was running (dryer replaced by a new one now )

My main question is : would you think such symptoms would be caused by a damaged PSU or a damaged Mobo ?

Thanks !

 

[GaryJohnson]

It sounds like a PSU problem to me, but the only way to be sure is to replace it. The PSU is probably cheaper and easier to replace than the motherboard anyhow. So even if you're not sure which it is, I think that would be the thing to replace first.

 

[pcgeek11]

My main question is : would you think such symptoms would be caused by a damaged PSU or a damaged Mobo ?

That is a definite Maybe.
I would suspect the PSU first as it is the first in line, but it could be the motherboard or nearly anything at this point.

I generally work from the easiest / cheapest component and work towards the hardest / most expensive component when isolating problems.

pcgeek11

 

[Guillaume]

Thanks for your answers !

So according to you none of those symptoms rules out one or the other, kind of confirms my fears.
And yes, starting with the PSU makes most sense, but I basically wanted to get some opinions before investing in the PSU and spending the cr4pload of time needed to extract my tower from its desk, and replace the parts (especially the mobo!).
If the Mobo is dead I'll likely build a complete new rig and I'm not sure the PSU I'd use would be the same as for the replacement.

Sigh, am the only one feeling this is the worst time to buy a new PC ?
I had hopes to wait a year so that my next one would be an affordable Core i7 + Win7 + array of SSD.. I hope it's the PSU !

 

[Guillaume]

Hey folks,

I thought I'd give you some news on the topic.
Changed the PSU yesterday (I so HATE Antec for designing an enclosure which forced me to remove 3/4 of my component to extract the PSU, including the CPU heatsink ! I hear that in their latest models you can remove both side panels, I'm sure they had received death letters ).

Could only do a few tests, but the SLEEP seems to work, so looks really promising !

The only downside is that the packaged Sonata PSU was driving the main enclosure fan speed, and it now runs à 100% speed with the associated noise.. will have to buy some throttler I guess.

G.

 

[CoinOperatedBoy]

Glad you solved your problem, definitely sounded like a PSU issue or even the case connector for the power/reset buttons.

As for your other comment, my personal opinion is that this is a great time to buy a new computer if you have relatively reliable income. Prices are very reasonable at the moment.