burnt CPU or mobo?

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Petras86

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Nov 28, 2010
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Okay, so I was connecting and extra fan to existing one inside the case with naked wires (i know- retarded and had it coming) and touched the CPU cooler with one of them (positive i think)... Saw some sparks in the contact area and PC rebooted... And then it kept rebooting every couple of seconds, and it's all it does now >.<
Disconnected everything and reset CMOS both ways- yup- same thing.
Can't think of a way to "borrow" a CPU to test- any suggestions?

Thanks.
 
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Chicano

Chicano

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If you were to attack a IDE/BIOS jumper to the two power button pins on the motherboard header... that's what you'd get.. so what got the worst of it, is probably the motherboard. But more tests should be done before giving up. See if resetting the BIOS and hard resetting the motherboard... that's remove the battery, remove the power cord, press the power button and hold it on for at least a full minute... wait 10 minutes and put the battery back on.

Another possibility is the PSU... as far as I know, the heatsink only makes contact with the CPU heatshield and that is not in direct contact with CPU circuits, so the discharge can't go through to the motherboard.
Look at it this way: You can safely touch the CPU heatshield but not the socket side (pins/balls)... it would be cautioned to touch the heatshield if it made contact with the CPU circuits. So, I don't think CPU or Mobo suffered any damage... The most likely component to suffer damange may be the PSU. When you jump the power switch header pins, what you actually switch on is the PSU...

If I'm wrong, I'd like to hear someone's opinion.
 
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Petras86

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Not sure what you are saying about the pwr switch. The part i touched with the wire was the top steel (?) plate of the CPU heatsink.
Sorry I didn^t mention: I tried my old PSU that I know is in working condition- same thing >.<
 
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Chicano

Chicano

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What I tried to explain is that jumping the power switch connections on the motherboard and leaving the jumper on makes a computer act the same way... so I thought the PSU had suffered the damage but if not, then the motherboad probably did, though I don't understand how that could happen because the top aluminum(!) plate of the CPU heatsink is isolated from the CPU internal circuits, or motherboard circuits. If it is to dissipate heat, it's not supposed to make contact but with the insulated CPU heatshield and nothing else.

But now that I think of it, the power discharge may have backed up to the PSU and found a way to overload something on the motherboard through the 24 pin connector, or even the CPU may have been affected through the 4/8 wire connector.

Another possibility is that the power switch may have been fused internally in the ON position, it's not so likely but you have to discard it. To test this last possibility, what I'd suggest is you try the following: Remove the Power Switch two wire connector from the motherboard front panel header pins, and with a small screwdriver or paper clip, momentarily touch the two pins on the motherboard header... the computer should start and if it stays on, the power switch was fused... if the same reboot cycle continues, then the motherboard was probably damaged... CPU damage is also possible but it's tougher and the motherboard has more sensitive components.
 
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Petras86

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Before posting this thread, I had already gotten to the point where the only connected to the mainboard things are the CPU with the heatsink and the 12 and 4 pin power cables. So no RAM or GPU or any USB or switch wires. Sorry again for not mentioning it...
The "other" PSU that I tried (still connected atm) is the one that came with the case and it did work for a while that I was using it.
Thank you for detailed suggestions, I appreciate them very much.
Next thing I will try is just to take out the mainboard and look for visible damage after work today.
Really hoping not to have to "upgrade" my 3570k nor the mainboard for the second time, since the first oine's one-in-a-thousand BIOS flashing disaster last summer >.<
 
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Chicano

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No RAM modules installed? Am I reading this correctly?... Don't think it will run without it.

One more thing: Have you checked if the CPU cooler fan runs? If the fan doesn't run, could be due to the electric shock taking out the fan motor... And short boot loops can also be caused by overheating... so, I just want to know if this is not the case.
 
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Petras86

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Yes, the RAM is removed, but it would not keep rebooting this way and it would beep-out a no-RAM code.
The CPU fan starts spinning but then the whole boot cycle stops and reboots. So there is also no way of it overheating since there is no reason to nor 2sec is enough to heat it up so much. Which would also cause a continuous beep.
My best hope is to find a blown capacitor that would be the SINGLE cause of all of this >.<
 
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Chicano

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It will also not run or even show any video without RAM.. so you can't diagnose anything like that.

The CPU can overhat in just seconds, and if it keeps rebooting the CPU doesn't have time to cooldown.. but if the fan runs, that is out of the question... The BIOS beeps suggest the CPU is OK and so is the BIOS... and if no RAM beeps are emited with i on, it to is probably OK. So, possible remaining cause is something in the motherboard. Capacitors can bulge, blow or leak from top or bottom so watch for any of these, and check for burnt motherboard components or spots but it may even have hidden damage... so there is no certain way to know what was damaged.. it may even be somethning very small and not show any sign of physical damage.. about the onl way to diagnose the damaged part is with a motherboard tester which are inexpensive and well sorth the price.
http://www.amazon.com/s?ie=UTF8&page=1&rh=n%3A172282%2Ck%3Amotherboard%20tester

 
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Petras86

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Okay, so I "scanned" entire mainboard with a magnifying glass and found nothing, of course. All the components that I managed to reach with a tester passed the current.
As I said- presence/absence of RAM is irrelevant in this case.
Gonna ask about possible repair prices tomorrow in one PC shop.
Damn summer heat- all this beacause of it -.-
 
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