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Is my mobo fried??

Last response: in Motherboards
August 25, 2009 10:35:58 AM


My pc won't power on anymore. I thought it was the psu so got a new one and still nothing. I know the psu gets power but I can't turn it on. Even the psu fan won't turn on.

Any ideas on how to test it. At which points should i check with a multimeter to see if the board gets power? My specs are in my sig.


More about : mobo fried

a c 156 V Motherboard
August 25, 2009 11:34:51 AM

What kind of PSU did you get?

The following is cut & pasted from a previous post.

Try to verify (as well as you can) that the PSU works. If you have a multimeter, you can do a rough checkout of a PSU using the "paper clip trick". You plug the bare PSU into the wall. Insert a paper clip into the green wire pin and one of the black wire pins beside it. That's how the case power switch works. It applies a ground to the green wire. Turn on the PSU and the fan should spin up. If it doesn't, the PSU is dead.

If you have a multimeter, you can check all the outputs at the back of the main power connector. Yellow wires should be 12 volts, red 5 volts, orange 3.3 volts, blue wire -12 volts, purple wire is the 5 volt standby. The gray wire is really important. It sends a control signal called something like "PowerOK" from the PSU to the motherboard. It should go from 0 volts to about 5 volts within a half second of pressing the case power switch. If you do not have this signal, your computer will not boot. The tolerances should be +/- 5%. If not, the PSU is bad.

Unfortunately (yes, there's a "gotcha"), passing all the above does not mean that the PSU is good. It's not being tested under any kind of load. But if the fan doesn't turn on, the PSU is dead.

August 25, 2009 8:15:48 PM

thanx jsc, the paper clip trick is awesome.

turns out my original psu is ok (its an ACBell 550W) and the new one aint (a gigabyte 550). Havn't yet got my hands on a multimeter yet. But when I do, which points on the mobo should i check?

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a c 156 V Motherboard
August 25, 2009 8:27:38 PM

Youcan check the 5 and 12 volts from a molex plug and you can check the rest from the back of the main power plug.
August 27, 2009 8:12:14 PM

hi, thnx for the replies

I've checked all the connectors and molex. All the volatges r gud (yellow +12, red +5). So do I conclude that the board is fried? keeping in mind that my replacement psu was a dud, i'm gonna try with another psu as well.

thanx again for all the help
a c 177 V Motherboard
August 27, 2009 10:53:00 PM

Maybe your front panel power switch has given up the ghost? Try removing its header, and mometarily shorting the two pins revealed, say with a small srewdriver blade - if the board powers up, you've found your culprit!

Good luck!