smthng wrong - cpu or motherboard

[AlexFa]

Hi

I'm having a problem.
I changed my friends HD (because it had a smart error) and put new cpu paste on it (really needed it)
As I took the cpu off, i saw a little bit, really just very little thermal paste on the cpu bottom (wtf?) and surely also some on the motherboard where the cpu fits in.
I removed the thermal paste very carefully with alcohol.

Then I closed everthing and wanted to start the pc. But it only went on for a second. Better said, nothing went on beside the fans, which spinned for a half sec. And after that, the fans are trying to spin again in an intervall of 1-2 sec. Spin, pause, spin, pause. After some time ive found out, that I can leave all cables plugged in everywhere, also the big motherboard cable, except the "pwr 1" cable (That thing with the 4 pins, i think its called cpu cable) and the pc gets power, but of course without the cpu cable there is nothing booting.

So whats broken, the motherboard, cpu? Something else?

Already done:
I have already changed the PowerSupply, its the same symptom with both

Thank u greatly in advance.

 

[Ketchup]

Are the pins on the board or on the CPU? Sounds like the paste may be causing a short either on the board side or the buttom of the CPU.

 

[VirtualLarry]

What socket is the CPU? If it's an Intel LGA socket, then you may have damaged or bent the pins on the mobo when you attempted to clean the thermal paste off, or the thermal paste may be causing a short somewhere.

 

[crashtech]

If you rubbed on the pins inside the CPU socket, there may now be bent pins. Not sure why CPU would need to be out just to refresh the thermal paste.

 

[VirtualLarry]

Hate to say it, but you may owe your friend a new mobo.

Edit: Why did you think that the CPU needed thermal paste? Was it overheating? Did it have "white paste" on before, and it was getting dried out, and you put some Arctic Silver 5 on?

AS5 is not strictly conductive, but it is capacitive, which can still screw up circuits if you get it on there.

 

[AlexFa]

Hi guys, thanks for all the answers.
thermal paste was dried out, and because i didnt want any thermal paste on the mother board im always taking it out, placing it in the original cpu plastic holder.

Im using the Gelid GC Extreme Paste

The mobo itself looks like this and has socket LGA1156:
http://h10025.www1.hp.com/ewfrf-JAVA/Doc/images/727/c01946063.jpg

So I think the pins are on the mobo.
Maybe some thermal paste is still on the bottom of the pins in the mobo. How do I get it out? The Thermal paste on the reverse side of the cpu plate had to be removed because this could cause many defects. :/

And Im sure i didnt bend any pins. I tiped very carefully with a alcohol soaked q-tips so the alcohol would do its job.

Thank you for other answers.

 

[crashtech]

Most thermal paste (or TIM, as we call it) is non-conductive, so while getting some in the socket is not good, it's not really worth the risk of trying to remove. Even if no pins were damaged, it is possible that the water component of the alcohol (most consumer alcohol contains significant amounts of water) was or still is creating paths for current, causing boot failure. The CMOS battery should be removed (and the power, of course) to forcefully clear the CMOS. Then the socket should be blown out and dried, perhaps with canned air and then a blow dryer, and carefully examined with a magnifying glass to definitely rule out bent or misaligned pins.

 

[Ketchup]

... And Im sure i didnt bend any pins. I tiped very carefully with a alcohol soaked q-tips so the alcohol would do its job...

So did you rub the q-tip on the pins or just on the bottom of the CPU? Rubbing q-tips over 1,156 tiny pins is not a good idea.

...thermal paste was dried out...

For future reference, this is normal. Thermal paste that is exposed (not doing it's job) will dry out. This doesn't mean that there is anything wrong with the thermal paste between the CPU and the cooler. Next time, if it's isn't broke, don't fix it. It sounds like all your friend needed was a new hard drive, and now he/she may need a new motherboard.

Look on bottom of the CPU and pins on the board for any signs of the q-tip you were using, or thermal paste. Really need to get that out now that it has been exposed. Hopefully the only problem is some paste that was left behind.

 

[AlexFa]

Ok thanks for all the answers.

I didnt rub anything, i tipped. And you havent seen the thermal paste haha , it was totaly dried out, no chance anyone could ignore it, and put the cpu fan back on it.
I have changed thermal pastes on cpu's about 18-20 times (friends) and this one looked really awfull.

Ill try get me a canned air, and after that use the blow dryer.
Im still asking me how he managed to get thermal paste under the cpu. I never changed cpu paste on his pc. (regrettably, damn him or the one who changed it and put thermal paste in it) But changed alot of broken hardware.

But good thing is, that cpu paste under the cpu is the explanation why my friend had sooo many not explainable problems with his pc, if I hadnt found that, that game with broken stuff would have gone on and on, way more expensive than a new mobo.

Maybe I can fix it.

 

[AlexFa]

Guys Thank you so much! Blowing the Mainboard Cpu with Canned air, and hair dryer made it! Its working again!

 

[crashtech]

Good for you! :thumbsup:

No more rubbing alcohol on CPU sockets!!!!

 

[Ketchup]

Great! Glad it is working.