Question Motherboard short circuit on USB - PC keeps crashes

Mar 25, 2019
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Hello and welcome all community!

My situation forced me to write a post here... Maybe some have an idea what is happening and give me a clue, but from beginning. I have an ASUS P6T6 WS REVOLUTION mobo + Xeon X5660 CPU + 12Gb DDR3 RAM + GTX 1060 GPU running Windows 10. This setup works flawlessly from beginning , but one day it changed. 3 months ago my friend by mistake "plugged" USB in a back of computer under motherboard (cause I forgot to put shield on a back). I was playing on PC and when it happened computer shuts down immediately and my friend saw a little spark. I unplugged power and waited for few minutes. Then I connected power plug and everything worked ok.
Next day I tried to play some games and after loading Windows threw BSOD "clock_watchdog_timeout". Also I noticed drops in FPS under load - didn't happened before. I perform full reset of BIOS and problem disappears till I turned game again. After some time (like 3 minuted) again - same BSOD. I tried to make some benchmarks in safe mode and there were no sings of problem. I reinstalled Windows and installed fresh drivers. Still - some situation.
I made CPU underclock (a little) turned off all ASUS boosting stuff, and then benchmark on CPU passed. PC was working for around 2 months but then : new BSOD appears. "machine_check_exception"

I checked motherboard, measured with multimeter for short circuit around all USB and it's look ok. Temps, voltage and others look fine. Memtest passed, "GPU only" bench passed. Also I noticed, when I plug USB drive, system randomly hangs but I'm not 100% sure that is caused by USB. I tried to unplug everything from back, turned off USB in BIOS and leaves only PS2 keyboard ( not using it for everyday work ) - same situation when I'm stressing PC.


I will be thankful if someone give me some advice to check something, replace, etc. I was thinking about replacing CPU (it's cheap as dirt) or buying new PCIe USBs but I'm not sure if that going to work - should I try? Is motherboard dead?
 
Mar 25, 2019
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Just a moment ago I take out a CPU (didn't done it before) and only one of a land was darker than others (from datasheet it was one of QPI data). I cleaned it and put back. I'm going to check it later if that help.

@jojesa , I'm trying to avoid replacement of motherboard but I think you're right. Giving it one more chance.

Photo of CPU:
2Hx35i1.jpg
 
Last edited:
Mar 25, 2019
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It's almost half an hour now since I had turned on benchmark. Before cleaning this test crashed PC after 2 - 3 minutes. I plugged in all devices like webcam, usb drive, phone etc. Nothing - no freezes, no crashes.

Looks like that pin had problems with communication. QPI is like a bridge between CPU and memory / chipset (if I understand it corectly).

Also, I installed Windows 7. I'm going to check it later under some games.


hcwh70S.png