Problematic motherboard or PS. Help please.

[Egnie]

A week or so ago my PC crashed for an unapparent reason, the screen wen black and the PC tried to reboot but there was no signal to the display. I noticed that no fans connected to the motherboard were spinning, only the ones connecter to the PSU. So I thought the motherboard had died. I had another motherboard with the same socket, memory types etc. so I tried swapping the motherboards, I installed everything on the new motherboard, tried to boot it but it didn't work. then I swapped back to the original motherboard and al of a sudden it booted and worded fine. Until about 48 hours later when I tried to play games on it, then it crashed after about 20 - 30 minutes or at random after 2 - 3 hours. And it kept crashing everytime I played a game on it, the screen would go black and a second or so after that, the sound would go and the PC would reboot and work fine again.

And now it crashed again, and the symptoms are the same as the initial crash, the motherboard connected fans wont work, and neither will the graphics card fan. But the standby light on the motherboard still lights up, so I'm guessing it's still getting power.

So far I have tested changing the CMOS battery and leaving the PSU of for 10 minutes or so. But I haven't gotten anything from it.

System specs:

Mobo: Asus M4n98td EVO
CPU: AMD Phenom II 960T
GPU: Gigabyte GTX 550 Ti
Boot drive: A-Data 128 GB SSD

So, what do you guys think may be the problem? I'm guessing the PSU or the Mobo...

Thanks in advance for any help.

 

[o1die]

Possibly the power supply. I usually have a spare for testing only. I find them cheap on craigslist. What brand and model do you have?

 

[WskOsc]

At first glance I'd say this may be the motherboard's power circuit on the fritz because of the fans not spinning but this can also be caused by a faulty connector on the power supply, and since you tried the components in a separate motherboard and they also wouldn't boot, blame would fall on your PSU.

Try disabling all Q-Fan controls in the BIOS to ensure that your fans are just running at 100% power all the time, that's the cheap and not likely to work solution.

The part I find interesting is that you say the GPU fan also doesn't spin after a reboot and this also implicates your PSU in a more major malfunction, likely requiring you to have the unit RMA'd or otherwise replaced.

As for the power-off/reboot issue itself, when the event occurs what exactly happens? When the sound fails after the screen goes black is there any loud pop or hiss or does it just cut out with no abnormal effects?

 

[Egnie]

At first glance I'd say this may be the motherboard's power circuit on the fritz because of the fans not spinning but this can also be caused by a faulty connector on the power supply, and since you tried the components in a separate motherboard and they also wouldn't boot, blame would fall on your PSU.

Try disabling all Q-Fan controls in the BIOS to ensure that your fans are just running at 100% power all the time, that's the cheap and not likely to work solution.

The part I find interesting is that you say the GPU fan also doesn't spin after a reboot and this also implicates your PSU in a more major malfunction, likely requiring you to have the unit RMA'd or otherwise replaced.

As for the power-off/reboot issue itself, when the event occurs what exactly happens? When the sound fails after the screen goes black is there any loud pop or hiss or does it just cut out with no abnormal effects?

When it crashes in a game it just goes black, the sound continues to paly normally for two - three seconds and then it just stops, not any wierd sounds or anything. I just stops and reboots.