So my friend is building a new computer and somehow he had two MBs fry. When the second one did it he found a short on the back side of the PCB right next to the 24 pin socket. Both MBs had the same short but he couldn't find anywhere in the chassis that it could have shorted on. He talked to the MB manufacturer (Asrock) and they suggested getting rubber insulators or non conductive standoffs. This seemed really strange to me. I come from a longstanding automotive background including being pretty familiar with the electronics side. At work I am involved in building and maintaining machinery with complex computer systems and I have built a couple of my own computers. Never in the history of anything have I heard of something like this being optional. If it's necessary or even in any way better then shouldn't it just always be done? If it's not necessary then why is it even an option?  
 

Sounds weird... More like a bad PSU or something...
 
See I use to use those nylon washers, to insulate it, thinking it'd short and crap.
 
But now I'm into audiophile stuff, and had tons of feedback. Well I took off the nylon washers, so basically the motherboard would ground to the chassis, and all the feedback is gone, and no shorts. Obviously you don't want any part of the motherboard touching the chassis besides where the mounting screws go. But yeah there's more to his issue than shorts from no nylon washers, cuz like I said, I never use them anymore and no issues.

your talking about asrock.....
 
asrock is to asus as Kia is to hyundai
 
hyundai owns kia but kias are made fun of for their horrible bad cars
 
same as asrock being the cheap brand of asus

It's impossible for a standoff to create a short that kills the motherboard unless it was a design flaw. There is enough clearance around the standoff holes to not allow that to happen. If anything, you'd just have an improper ground.
 
First thing I'd suspect is the PSU.

The PSU sounds more like the problem.

Thanks guys. I was more interested in the insulator idea than diagnosing his problems so I didn't go into great detail on his build.
The one thing that is odd is he tested both boards out of the chassis and they worked fine. He put them in the chassis and they both instantly popped. This makes me think the PSU is unlikely unless maybe it's somehow leaking voltage into the chassis or something. Whatever the case he is getting a new tower, PSU and mobo this time plus using the insulators as per Asrock's recommendation.
Seeing the metal contacts on the MB holes I always assumed they were designed as ground points.
Why would they even make these insulators is what I'm still wondering about?

yoshimitsuspeed


Thanks guys. I was more interested in the insulator idea than diagnosing his problems so I didn't go into great detail on his build.
The one thing that is odd is he tested both boards out of the chassis and they worked fine. He put them in the chassis and they both instantly popped. This makes me think the PSU is unlikely unless maybe it's somehow leaking voltage into the chassis or something. Whatever the case he is getting a new tower, PSU and mobo this time plus using the insulators as per Asrock's recommendation.
Seeing the metal contacts on the MB holes I always assumed they were designed as ground points.
Why would they even make these insulators is what I'm still wondering about?

 
I would try it without the insulators. With a new power supply. I am pretty sure it is a voltage leak from the power supply.

You could also try building outside the case. That would eliminate whether it is a grounding issue or not.

I would inspect the motherboard tray and see if there was contact with the tray and Mobo causing the short...
 
If so insulate the tray with tape or a plastic stick on liner type material to prevent backside shorts.
 
Also are you positive that all mobo standoffs are in the correct place, they are usually movable, and one may be hitting the back of the mobo and shorting it out 

ARchamps


You could also try building outside the case. That would eliminate whether it is a grounding issue or not.

 
He did and he said it worked. Its most likely the Poser supply sending voltage to the ground.  I have had my fair share of those
 

killerjas

ARchamps


You could also try building outside the case. That would eliminate whether it is a grounding issue or not.

He did and he said it worked. Its most likely the Poser supply sending voltage to the ground.  I have had my fair share of those

 
I know it was just a typo but for a bad power supply it also fits. 
 
Also just to add the the thread I've been building my own systems since the early 90's and haven't used any of those little washers in ages.

LOL sorry. Typed to quick apparently. LOL

Since it happened to the 24pin power connector in the same place on two boards, it's almost guaranteed to be the PSU.
 
Keep in mind that most motherboards ground to the case through the motherboard screws when you install them.  The PSU's own housing is grounded to the wall, and through that the entire system is grounded to your outlet as long as brass standoffs were used and the case uses a metal motherboard tray. On really cheap motherboards you can even detect some leakage grounding through the case / PSU housing.
 
 

Nex_Lupus
your talking about asrock..... 

asrock is to asus as Kia is to hyundai

hyundai owns kia but kias are made fun of for their horrible bad cars

same as asrock being the cheap brand of asus

 
ASRock has come a long way in the last few years, check out their Extreme11 mainboard for example. ASRock is the 3rd largest motherboard manufacturer now as well, well ahead of MSI and the rest. ASUS spun off Pegatron a few years back and so ASUS no longer has anything to do with ASRock.