Cooked P/S

One issue to check first if you haven't already:

If all these power supplies were plugged in to the same outlet (or power strip/surge protector, you might want to test and make sure you are getting clean power to the P/S.

The M/B could cause the problem if the power regulator on the board is fried or if there is a fault (short) somewhere in the primary power circuitry for the board.

One other thing to check (maybe save some money while you are troubleshooting. If any of the power supplies are out of warranty, you might try opening it up (carefully) and see if there are any blown fuses that you can replace (i.e. not soldered in. If so, while I wouldn't trust the P/S for long term use, it might be useful as a troubleshooting replacement once you replace the blown fuse.

I would also check out the web page for the M/B manufacturere to see if there are any known issues with their motherboards.

Of course, the problem you are stuck with is did the original P/S fail and somehow take out the M/B, which caused the failure of the 2nd P/S, or was the M/B at fault to begin with?The only way you may find out is to take both the failed P/Ss and the M/B to a computer repair shop that has the necessary tools to test such things. Unfortuately, if you try a warranty claim with either the M/B vendor or the P/S vendor first without a repair shop's opinion (or test results), you may end up in a finger-pointing game with each vendor blaming the other for the problem.

Good luck.

The power supply can protect itself (not every time) if abnormal consumption is occurred.
Also the problem with your motherboard can come from others equipment attached to computer: printer, monitor, etc. or from a wrong mounting of the motherboard in case (short caused by screws or case).

Hi,

FYI, The motherboard doesn't "return a charge" to fry the powersupply.

What has possibly happened is that your motherboard's circuitry has "shorted". I'll explain.

Anything electronic "uses" the energy sent to it. In the case of a lightglobe, the power supply (your power company) sends power to your light and your lightglobe "uses" it by converting it to light.

In the case of a PC, it takes energy to repeatedly flip those billion little switches inside it. The transistors in thechips in there...

Also it takes energy to spin the fans and so on...

If/when your motherboard blew up, it blew up in such a way as to lay a piece of metal across the +ve and -ve terminals of the supply.

So now, instead of pushing all that energy into the motherboard (where it gets used) all the energy simply goes through that metal and returns to the power supply!

Power supplies dont like that.

Some will blow a fuse. Some trip a circuit breaker, but cheaper ones make a zzzt noiseand then smell funny :-)

I dont know whether that explanation has helped you.... but it would be worth your while checking around the motherboard for blackened spots - especially in the area where the power supply connects to the motherboard. Sniff it too. Burned out parts have a characteristic smell.

Cheers,
Tim.