Fried MOBO and new PSU?

[ericfree]

My 5 year old rock solid computer finally gave out.
I smelled this strong burning smell, and then 30 minutes later the computer just shut off.
Upon trying to reboot, nothing happened at all. No fans, no beep -- nothing.
I took it to CompUSA, and they hooked the PSU up to a PSU tester and said the PSU went out.

So I bought a new PSU, took the computer back home, made all the connections, and tried to boot -- the same -- no fans, no beep, no nothing. So, I returned the PSU and got my money back.

So I think perhaps the MOBO is fried?

Now it's a month later, and I'm building my own new computer, and I know a lot more about the insides of computers, so I'm tempted to try to power up the beast again.

My question: If the MOBO is fried, can hooking up a PSU to it damage the PSU??

[Alaron]

No, you cannot damage a PSU with a dead board. It is possible that the replacement PSU was a poor quality unit that could not boot the board. This is especially possible with a generic CompUSA unit. There is a chance that the board is still alive.

Can you give us some specs, including brand/wattage of the power supplies involved?

[Cricket]

Originally Posted by ericfree So I think perhaps the MOBO is fried?

It's a possibility.

Originally Posted by ericfree My question: If the MOBO is fried, can hooking up a PSU to it damage the PSU??

Are you sure the motherboard is fried?

What brand was the power supply? Cheap low quality power supplies don't have over-voltage protection and can fry other components when they die.

A fried motherboard shouldn't damage a new power supply since it's already dead...but there is always the chance that it could damage a new power supply.

Cricket

[ericfree]

The PSU I bought from CompUSA was an Antec for about $100.

Now, I've tested my original PSU -- I shorted pins 3 and 4 on the ATX connector and the PSU fans start spinning, and I've measured all the correct voltages on all the pins of the 20 pin ATX connector. (See: http://www.ochardware.com/articles/p.../psuvolt2.html )

So now, I suspect the PSU might be OK. Then I hooked it up to the MOBO (AOpen AX4B PRO-533) -- just the ATX12V - 20 pin main connector and 4 pin secondary connector. I disconnected all the hard drives, optical drives, FDD, and just to see if anything would power up. Same result -- a little LED light comes on on the MOBO when I turn on the PSU, but when I short (with a screwdriver) the SPWR pins to start the computer (these are the two pins that the power switch was hooked up to -- I used this method instead just in case the power switch itself had gone bad) nothing happens, no fans, nothing. Is the conclusion the MOBO is for the garbage heap, or is there anything else that can be tried?

[Cricket]

It sounds like the motherboard is dead.

Cricket