Simple Motherboard test?

[bsi]

My brother had a power failure and now his computer won't start up. I suspect a fried motherboard but don't know how to check.

It is an e-machine H2602 if that matters. When you try to power it up, there is no activity whatsoever. No fans, no bios, no beeps.

It is a 250W power supply. I swapped in an old one I have but it only had the 20 pin connector, not the extra 4 pin connector (for P4's?). I expected it to at least spin up the CPU fan, even without the extra 4 pin connector. However, the same zero activity, even with the substitute power supply.

My next step is to manually power it on via shorting out the pins but I wanted to ask the groups opinion before I do that. I am reluctant to disassemble my main PC to extra a power supply with the extra 4 pin connector.

Is there a simple test for a fried motherboard? Or a fuse somewhere ( I have never seen anything user replaceable on a motherboard.

Thoughts?

 

[Gerald]

The fuse is in the power supply.

I've blown two power supplies within the past year. It's a lot more common for a power supply to fail than the motherboard.
E-machines are cheaply made so it's probably a very low end power supply.

 

[bsi]

His power supply works in my test machine so it is probably not that.

I agree that e-machines don't last. I buy them myself because I know I am going to obsolete them in two years but the three that I have bought for family over the years have all failed.

Thanks for the reply though.

 

[chuck007]

Hmmm - The Power Supply would be my first suspect, so I would try one with the 24 PIN output on the existing M/B and it may work.

I've had to replace PSU in an one eMachine and hard drive in another eMachine (I think it was a WD 20G drive) in another. I belive the PSU I replaced was a micro ATX that seemed a bit underpowered (maybe 150W), but my memory is getting foggy.

Good luck.

 

[chuck007]

A quick thought. Inspect (visually and smell) the TO220 voltage regulators on the mothboard near the PSU connector. Since you suspect it was a power event, it is possible the PSU surged the voltage and blew the step down 5V or 3.3V regulators.

I've seen this before (rarely), and it was smell that tiped me off. The odour of the regulators led me to look very closely; only then did I spot cracks and ruptures on the voltage regulators. I salvaged the RAM and CPU and tossed the M/B.

 

[chuck007]

Yes - Connect all the power pins it needs (you can buy a 20 to 24 pin adapter for about $10 if you need one).

Also, if your M/B has a separate ATX12V 4-pin power connection for powering an Onboard video chipset, it also needs to be connected. Hours can be wasted if you forget... (been there, done that, lesson learned).