Bad PSU shorting out MOBOs

[gbferrell]

Has anyone had experience with a shorted power supply destroying a MOBO? I removed a PSU from a dead computer and installed it to a known good computer. Now that computer sounds like it's running as soon as I plug the power cord into it (without pressing the power button) but otherwise is dead- no video or anything.

 

[Motopsychojdn]

not had it myself, but its very possible,
I would've tested the psu in question on its own,not put it in a working unit though
Moto

 

[gbferrell]

I've never run across this problem before and I don't recall reading about anyone else ever having it. Online searches haven't helped much either- apparently it's a very rare problem. I tested the original computer with a known good PSU and when it wouldn't start with that, I mistakenly assumed that the MOBO was the whole problem. Since we are short on spare PSUs and cash around here, I wanted to save the original PSU for other systems and wanted to make sure it worked before I saved it.

Using 20/20 hindsight, I did a multitester pinout test and one of the +5 volt pins read about 8 volts. That is several volts above tolerance and is probably what ruined the boards. I'm going to have to be more careful in the future. Fortunately, the systems I ruined are older systems that already had problems so it's not a huge loss but I would've liked to be able to fix them. Now that doesn't look like a feasible option.

 

[Motopsychojdn]

Sorry about that man, but if nothing else you've learned for future to get your multimeter out for psu problems first may save a more expensive system from the same fate down the road
Moto

 

[gbferrell]

Yes, you are right. Also, A better name for the subject of this topic would've been: "Bad PSU RUINS motherboard" since it's not certain whether the PSU was actually shorted or whether its overvoltage caused a 'short' or an 'open' in the boards. Had I used a multitester before I posted, I would've given a more accurate subject line. Also, had I searched on line with the updated subject line (instead of using the search term 'shorts') I would've found this forum posting:

http://www.velocityreviews.com/forums/t227979-can-a-bad-power-supply-ruin-the-motherboard.html

There I would've seen that this is a fairly rare, but not impossible, phenomena.

 

[Motopsychojdn]

Yup, Its a double-edged blade that electrickery stuff
Well, Were here for your next build if you need us man
Moto

 

[gbferrell]

Best answer selected by gbferrell.

 

[gbferrell]

Thanks Moto

 

[Motopsychojdn]

no problem man, thank you for B.a
Moto

 

[gbferrell]

You are welcome.

 

[gbferrell]

BTW, I don't see much progress on your Attempting to give a damn meter. Better reboot.

 

[Motopsychojdn]

I saved it as a gif image (Fail hehe) originally,
you've inspired me to change it, should be working soon
Moto

 

[gbferrell]

I was only kidding, I hope you know, - don't change it- it's funny!

 

[euclidsbrother]

I've never run across this problem before and I don't recall reading about anyone else ever having it. Online searches haven't helped much either- apparently it's a very rare problem. I tested the original computer with a known good PSU and when it wouldn't start with that, I mistakenly assumed that the MOBO was the whole problem. Since we are short on spare PSUs and cash around here, I wanted to save the original PSU for other systems and wanted to make sure it worked before I saved it.

Using 20/20 hindsight, I did a multitester pinout test and one of the +5 volt pins read about 8 volts. That is several volts above tolerance and is probably what ruined the boards. I'm going to have to be more careful in the future. Fortunately, the systems I ruined are older systems that already had problems so it's not a huge loss but I would've liked to be able to fix them. Now that doesn't look like a feasible option.

Gah.. i think this exact thing happened to me. My system (home built) was nearly 6 years old and runs pretty much 24/7. Came home one day and it was off and would not turn on. Tried multiple PSU's and nothing.. board would not power on. So got a new mb/cpu and memeory (upgrade from amd fx to ryzen), put it all together with same PSU. As soon as I turned it on, it started smoking around the memory chips (near 24 pin PSU connector). Now that board is dead too. Hoping it didn't take the CPU and memory with it.

Haven't had a chance to test the voltages yet. Lesson learned. Never had something like that happen before.