Possible Motherboard Failure ?

[clutchc]

Lately, my desktop computer has been failing to start when I press the start button. Nothing happens. No lites, no fans, no noise, nothing. And, it will fail to start more often than it starts. I first thought maybe the Power-on Switch was the culprit, so I removed it along with the wires/connector and tested it with an ohmmeter. Works fine. Makes and breaks every time. My Asus P5N-E 650i-SLI mobo has a connector like most boards do, where you plug in the pair of wires/connector from the Power-on Switch. So, I tried shorting the two pins that the switch plugs onto. Most of the time, nothing. But about once in every 10 or 20 attempts at shorting the pins, I can get the computer to start and boot up. So... here's my question; do I assume the problem is in the motherboard? Or am I missing something else I should check?

My system was factory built with plenty of cooling, nothing is overclocked, and the power supply is a good quality 850w unit. Temps are always normal.

 

[T_T]

Before assuming the mobo is dying, a good place to check is our standard troubleshooting checklist. Follow the link in my signature to check out the troubleshooting guide.

Although the Forum is "homebuilt" the guide is still a good place to check. I suspect a failing power supply, but check out the guide anyway. If your system still has warranty on it, you may want to consider using it, because opening the case and tampering with the hardware may void your warranty.

If you do perform these steps and nothing helps, try the breadboarding link at the bottom of the guide. Chances are that if you've completed each step in the troubleshooting guide and performed the breadboarding, you do have a failing mobo.

Good luck.

 

[clutchc]

Before assuming the mobo is dying, a good place to check is our standard troubleshooting checklist. Follow the link in my signature to check out the troubleshooting guide.

Although the Forum is "homebuilt" the guide is still a good place to check. I suspect a failing power supply, but check out the guide anyway. If your system still has warranty on it, you may want to consider using it, because opening the case and tampering with the hardware may void your warranty.

If you do perform these steps and nothing helps, try the breadboarding link at the bottom of the guide. Chances are that if you've completed each step in the troubleshooting guide and performed the breadboarding, you do have a failing mobo.

Good luck.

Thanks. I'll check it out. As far as the warranty, my computer has long ago lost it's warranty. I've upgraded almost everything removable

 

[clutchc]

Before assuming the mobo is dying, a good place to check is our standard troubleshooting checklist. Follow the link in my signature to check out the troubleshooting guide.

Although the Forum is "homebuilt" the guide is still a good place to check. I suspect a failing power supply, but check out the guide anyway. If your system still has warranty on it, you may want to consider using it, because opening the case and tampering with the hardware may void your warranty.

If you do perform these steps and nothing helps, try the breadboarding link at the bottom of the guide. Chances are that if you've completed each step in the troubleshooting guide and performed the breadboarding, you do have a failing mobo.

Good luck.

I used my Antec PSU tester on the motherboard power connector and got a result showing the +12v2 rail as flashing "LL". Is this an indication of a faulty PSU or does the 2nd +12v rail not go to the mobo? My power supply is an 850w epower EP-850 XP w/4 +12v rails. My mobo is Asus 650i.

 

[T_T]

The "LL" means that the detected voltage is lower than minimum value, IE that +12v rail isn't working correctly. This would indicate that your PSU is faulty.

 

[clutchc]

The "LL" means that the detected voltage is lower than minimum value, IE that +12v rail isn't working correctly. This would indicate that your PSU is faulty.

I guess I better start looking then. Thanks. I would like to go to a modular PSU. Most good ones all have a top mounted fan. My case requires the PSU be mounted on top, but the top of my case is closed. Would it hurt to mount it upside down so the fan faces down into the case? Does the fan draw air in or exhaust air out?

 

[T_T]

ATX PSU have rear mounted fans because of the ATX case structure. Mounting your PSU upside down isn't a good idea, but if you can accomplish it then doing so certainly would be better than the having the exhaust fan facing the top of your case, which of course traps the air and causes more heat.

ALL PSU fans are exhaust because of the massive amount of heat generated by the PSU.

 

[clutchc]

Best answer selected by clutchc.