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"fried" CPU. Is this possible?

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January 15, 2012 4:04:58 AM

My brother, once again, became so annoyed with his computer that he yanked its power cord plug from the wall outlet. Doesn't matter how many times he has been advised by techs and myself to not do this. He did it again anyway. The CPU would not turn back on ... it wasn't even getting any power. He took it to a reputable place and was told he had probably fried some components, and that the cost to fix it would be around $400 (US). He was advised that it would be a better idea to buy a new, inexpensive CPU and transfer any data he could get from the fried one to the new one.

Anyway, can one truly fry a CPU by yanking its power supply instead of gently turning it off properly? :( 

More about : fried cpu

January 15, 2012 4:17:32 AM

lakemono said:
My brother, once again, became so annoyed with his computer that he yanked its power cord plug from the wall outlet. Doesn't matter how many times he has been advised by techs and myself to not do this. He did it again anyway. The CPU would not turn back on ... it wasn't even getting any power. He took it to a reputable place and was told he had probably fried some components, and that the cost to fix it would be around $400 (US). He was advised that it would be a better idea to buy a new, inexpensive CPU and transfer any data he could get from the fried one to the new one.

Anyway, can one truly fry a CPU by yanking its power supply instead of gently turning it off properly? :( 


Fry? No

Short out? Possible.

Will it make a difference to you? Not really :( 
a c 118 à CPUs
January 15, 2012 4:27:08 AM

you can certainly damage a pc and kill a cpu by yanking the plug as it will cause a power spike up the neutral wire as the circuit is broken... the protection in a pc is based on the live wire going in. there is no protection on the out/neutral. best thing you can do is point and laugh at him... he has just learned an expensive lesson and laughing at him will remind him not to be a tit and loose his temper on an inanimate object.
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a c 152 à CPUs
January 15, 2012 5:01:49 AM

Sounds like he screwed up important hardware probably through a power surge. The only thing he can do now is replace the broken hardware or get a new computer.
a b à CPUs
January 15, 2012 7:32:39 AM

only need to replace the power cord of psu and it will good to go (if other components are OK)
a b à CPUs
January 15, 2012 8:43:16 AM

Leave the psu unplugged for a while or test it in another system. Or check the plug it self where it was inserted. Specially at the DB maybe where it might have tripped
January 15, 2012 9:42:10 AM

Assuming the PSU has short circuit protection which I believe most do, no components on the MB should have been damaged. Try hooking up a different PSU to the MB. Pulling the cord from the wall is basically the same as hitting the power switch on the back of the PSU. You might find the reputable pc shop is just trying to make a quick buck off your brother.

You say the cpu doesnt get any power, like I mention above, check the PSU is even switching on by removing the main connector from the MB (and all other connectores), and short out the green wire with any black one on in the connector. If you have a multimeter, you can also test your voltages though this will be pretty much be useless even if the voltages are correct since the PSU is unloaded.
a c 172 à CPUs
January 15, 2012 9:44:43 AM

truegenius said:
only need to replace the power cord of psu and it will good to (if other components are OK)

The power cord is almost certainly the only component that you know is good.

More than likely, the CPU and RAM is good. PSU, motherboard, and drives are another matter.

If you want to try to troubleshoot:

Work systematically through our standard checklist and troubleshooting thread:
http://www.tomshardware.com/forum/261145-31-read-postin...
I mean work through, not just read over it. We spent a lot of time on this. It should find most of the problems.

If not, continue.
The following is an expansion of my troubleshooting tips in the breadboarding link in the "Cannot boot" thread.
http://www.tomshardware.com/forum/261145-31-read-postin...

I have tested the following beep patterns on Gigabyte, eVGA, and ECS motherboards. Other BIOS' may be different, but they all use a single short beep for a successful POST.

Breadboard - that will help isolate any kind of case problem you might have.
http://www.tomshardware.com/forum/262730-31-breadboardi...

Breadboard with just motherboard, CPU & HSF, case speaker, and PSU. Breadboard with just motherboard, CPU & HSF, case speaker, and PSU. At this point, if you do not have a system (internal case) speaker, you really need one.


Make sure you plug the CPU power cable in. The system will not boot without it.

I always breadboard a new build. It takes only a few minutes, and you know you are putting good parts in the case once you are finished.

You can turn on the PC by momentarily shorting the two pins that the case power switch goes to. You should hear a series of long, single beeps indicating memory problems. Silence indicates a problem with (in most likely order) the PSU, motherboard, or CPU. Remember, at this time, you do not have a graphics card installed so the load on your PSU will be reduced.

If no beeps, LED's, or fan activity:

Check for line power at the PSU input. Extension cords, power strips, and power cords do fail.

If you have power and no beeps, suspect components in likely order are PSU, motherboard, and CPU.

Running fans and drives and motherboard LED's do not necessarily indicate a good PSU. In the absence of a single short beep, they also do not indicate that the system is booting.

At this point, you can sort of check the PSU. Try to borrow a known good PSU of around 550 - 600 watts. That will power just about any system with a single GPU. If you cannot do that, use a DMM to measure the voltages. Measure between the colored wires and either chassis ground or the black wires. Yellow wires should be 12 volts. Red wires: +5 volts, orange wires: +3.3 volts, blue wire : -12 volts, violet wire: 5 volts always on. Tolerances are +/- 5% except for the -12 volts which is +/- 10%.

The gray wire is really important. It should go from 0 to +5 volts when you turn the PSU on with the case switch. CPU needs this signal to boot.

You can turn on the PSU by completely disconnecting the PSU and using a paperclip or jumper wire to short the green wire to one of the neighboring black wires.
http://www.youtube.com/watch?v=5FWXgQSokF4&feature=yout...

A way that might be easier is to use the main power plug. Working from the back of the plug where the wires come out, use a bare paperclip to short between the green wire and one of the neighboring black wires. That will do the same thing with an installed PSU. It is also an easy way to bypass a questionable case power switch.

This checks the PSU under no load conditions, so it is not completely reliable. But if it can not pass this, it is dead. Then repeat the checks with the PSU plugged into the computer to put a load on the PSU.

If the system beeps:
If it looks like the PSU is good, install a memory stick. Boot. Beep pattern should change to one long and several short beeps indicating a missing graphics card.

Silence, long single beeps, or series of short beeps indicate a problem with the memory. If you get short beeps verify that the memory is in the appropriate motherboard slots.

Insert the video card and connect any necessary PCIe power connectors. Boot. At this point, the system should POST successfully (a single short beep). Notice that you do not need keyboard, mouse, monitor, or drives to successfully POST.
At this point, if the system doesn't work, it's either the video card or an inadequate PSU. Or rarely - the motherboard's PCIe interface.

Now start connecting the rest of the devices starting with the monitor, then keyboard and mouse, then the rest of the devices, testing after each step. It's possible that you can pass the POST with a defective video card. The POST routines can only check the video interface. It cannot check the internal parts of the video card.
a b à CPUs
January 15, 2012 9:47:37 AM

floatpoint said:
You might find the reputable pc shop is just trying to make a quick buck off your brother.


+1 [:truegenius:6]
a b à CPUs
January 15, 2012 9:58:46 AM

@ jsc

"The power cord is almost certainly the only component that you know is good. "
yes in normal cases , but since op's brother "yanked its power cord plug from the wall outlet" which can cause a break in wires (copper wires inside insulation).

Why i made this reply, because it happened to my headsets and problem was in the cord (internal damage)
January 23, 2012 3:50:49 AM

Thanks to all of you for your replies, especially "i can has beer" moderator. I have exacted a sworn pledge from my brother that he will let me tinker with his dead computer. Gotta go. Sorry.
January 23, 2012 3:56:10 AM

Okay. I'm back. Family member needed something.

I truly can hardly wait to see what I can do about diagnosing the problem(s) and hopefully fixing them.

Thanks again.
a b à CPUs
January 23, 2012 5:49:50 AM

Im guessing its just the psu or the mobo.

test the psu, if it still doesn't work then replace it. if it does then you might as well have to get a new mobo to test somehow.
March 3, 2012 3:51:05 AM

I printed out the instructions, read them, and then my eyes glazed over. I am sending the link to this thread to my good cousin Bob (self-proclaimed computer geek). He has offered to walk me through all the steps ... but this would take hours, as he is in South Dakota, and I am in California, and thus we would be communicating by phone. Doesn't sound appealing to me at all. But he wants to read this thread, so I am going to send it to him.
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