Is the motherboard bad??

[PPD3195]

Have a desktop machine that is acting weird. It wouldn't power on yesterday. The power supply fan would spin up for about a second and then it all would stop. Figured it was the power supply so I put a new one in and it does the same thing. Pull it out to return it to best buy, put the old one back in and it powers up! Two days later and it won't power up again...same problem.

So, am I dealing with a bad motherboard? I'm not sure what else it could be...

Thanks!!

 

[o1die]

You'd better escalate the issue with best buy and stop messing with it yourself. If it's still under warranty, let them fix it. Describe the symptoms exactly as they happen; the system needs to be warmed up thoroughly before it happens, so let Best Buy know that. Replacing a newer oem board yourself is too expensive, and the windows installation is tied to a small bios file that identifies your motherboard as geniune hp or whatever brand you have. Good luck.

 

[PPD3195]

Let me clarify...this is a machine I built myself and is several years old. I bought the replacement power supply from Best Buy. After installing the new power supply and still having the same issue I took it back.

I've been building my own machines for years and I'm just looking to make sure I'm not missing something with this particular troubleshooting issue.

Basically, if the machine powers up for a second and then shuts down and it's not the power supply, it's gotta be the motherboard...right? Am I missing anything?

 

[Traildriver]

Because it is several years old I would recommend reseating everything on the pc. Even replace the thermal paste and double check the MB mounts.

Thermal expansion/contraction due to use (on/off ccyles) and the odd computer move from place to place could have loosened something.

 

[o1die]

Good. Sorry for my confusion. I would take the board out and place on a wooden surface (such as a breadboard) or on top of the cardboard box it came in. Leave just one stick of ram in the slot closest to the cpu, maybe the keyboard, cpu/heatsink, and try onboard video if your board supports it. I touch the case connection cluster of pins and move it around with a screwdriver until the board fires up. This procedure elimates the posibility of shorts caused by the board touching something inside the case. If it posts and stays on, then check your case for a loose standoff, uneven standoff (different height from the others) and replace or remove if needed. You only need 4-5 standoffs to mount a board properly; you can leave some holes without a screw on the board. Also check the position of the cmos jumper using the board manual for reference. Most have 3 pins, and sometimes the wrong ones are covered at the factory to keep the motherboard battery from running down.

 

[PPD3195]

Thanks, guys! I'll check on that stuff. Some of it I think I've ruled out having put a brand new PSU in and it still having the same problem. It just seems so weird for something like this to be intermittent.

o1die, I'm hoping you've nailed ti with something shorting out somewhere which would explain why it comes and goes.

I'm wondering if it could be the video card since it requires that 6 pin power...? Not sure if I have a spare laying around to test it and no on-board with this MB. I did try putting it in the second PCIx slot before I switched PSU's, but that didn't help.

Thanks again!

 

[pepe2907]

How about the power grid at your place?
If your supply would work near it's limit in normal conditions even a slight underpower by the grid may trouble normal system startup.

 

[PPD3195]

How about the power grid at your place?
If your supply would work near it's limit in normal conditions even a slight underpower by the grid may trouble normal system startup.

Don't think it would be the power. I have a clean power unit on my home theater and it never reads low on voltage. The computer has also been working well for about a year in this location. It's also a fairly basic machine so I can't imagine it's pushing the PSU to limits.