Need help troubleshooting my hardware...

D

DarkWhisperer

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My PC was incredibly dusty and the fans were starting to grind. So I knew a spring cleaning was required. Im quite familiar with the inside of a PC, so I had no problems taking it apart, cleaning off the dust (gotta love canned air), and putting it all back together. However, on startup, the power comes on for about 2 seconds, and then goes off for about 4 seconds, then on again for 2 seconds, and then off, and round and round. So somethings wrong. Removed all uneccesary components like HDD's & graphics to try to get it to POST. But no luck. Tried using just 1 stick of RAM, and swapping those around, no luck. So either its my CPU or motherboard thats gone.

So the question is, which one is it and how do I tell? Can a motherboard power up and idle without a CPU? Is there something else I should be looking at, like my PSU perhaps?
 
Make 100% sure that your CPU's heatsink is properly secured, otherwise your CPU might overheat within 2 seconds.
 
Something similar happened to me and it was becaus there was no RAM in the machine at all :p Sounds like you have that coverered though, so as Pada said, check the CPU heatsink. And might as well double check all the other connections as well.
 
Well, its funny that you should mention that. When I took the heatsink off, I discovered that despite all the guides saying that you should put as little paste as possible, I had put too little. It only covered about two thirds of my CPU. Despite that it worked great for 2 years. However, when I look at it now after putting it back together, it looks like its sitting slightly unevenly on my CPU. Problem is, I have no idea how to fix it. Everything is exactly as it should be. Maybe I'll take it all apart again and go through the process more slowly and carefully.
 
Two thirds is PERFECT. Only the very center of the CPU Integrated Heatsink (IHS) gets hot since the actual CPU cores sit just under there, hence 99% of the heat gets transferred from the IHS to the heatsink in the middle. Remember that metal to metal thermal transfer is roughly 10 times better than metal to paste to metal thermal transfer
 
Could be the board is shorting on the case too :)
 
SharkBait said:
Your power button is stuck!
Click to expand...

What?? Its a click button, so I press the button, theres a click, and the PC starts up while the button comes out. Nothing special. Could this be caused by the power connector to the MB being backwards? I did try facing the connector in either direction when attached to the MB, didnt make any diff. I"ve got a spare case I can put my setup into, to check if indeed the power button is sticking.
 
It could be a snipped wire or a loose molex connector shorting the rig. Built a rig for someone and had the exact same symptoms only to discover that one of the front panel cables wasn't shielded anymore. A bit of insulation tape solved the issue
 
robdutchmonkey said:
It could be a snipped wire or a loose molex connector shorting the rig. Built a rig for someone and had the exact same symptoms only to discover that one of the front panel cables wasn't shielded anymore. A bit of insulation tape solved the issue
Click to expand...

Interesting. Alright, I guess Im trying my rig out in another case. Thanks for the ideas guys :)
 
DarkWhisperer said:
What?? Its a click button, so I press the button, theres a click, and the PC starts up while the button comes out. Nothing special. Could this be caused by the power connector to the MB being backwards? I did try facing the connector in either direction when attached to the MB, didnt make any diff. I"ve got a spare case I can put my setup into, to check if indeed the power button is sticking.
Click to expand...

The power connector on the board can't be backwards, it can only fit in one way. If it could, you would end up with some serious damage.

If you mean the little jumper-type connector from the button to the motherboard, that can be in either way, it doesn't matter. My money's on the CPU's thermal kill-switch kicking in, since you mentioned something earlier about the fan not being on properly? A modern desktop CPU without a fan will overheat almost immediately.
 
So then, Plan A, try the PC with my Intel heatsink, rather than the aftermarket one. Plan B, try it in a new case. I was talking about the power-on jumper, not the power-connector from the PSU.

After a bit more thought, I dont think its the heatsink. After I removed the heatsink when I encountered this problem, the paste I had applied had spread pretty well on the CPU. So I doubt the heatsink isnt contacting properly. On the other hand, the 2-3 seconds of power does seem right in terms of the CPU overheating & killing the power. We'll just have to see.
 
Thermal protection is unlikely to kick in and shutdown on a cold start unless something has gone critically wrong. It really does sound like more of an electrical fault
 
It might not be the paste, it could be that one of the clips/screws of the heatsink isn't inserted properly, that would be why the heatsink looks uneven as you said. You didn't mention what CPU, cooler and board you were using, but the stock Intel ones with the clips, can be tricky to replace sometimes.
 
I thought you have tried the other power button by now? You don't even need another power button, just use a screw driver to short out the 2 pins where the power button connects and see if it stays on...?
 
Well, CPU = I7 920, MB = Gigabyte GA-X58-UD3R, Cooler = Noctua NH-U12P SE1366.

The heatsink fins looks straight and parallel to the rest of the components. But when I look closely at the base which contacts with my CPU itself, it looks like its slightly off. So trying the default Intel Fan will help answer the overheating line of thought.
 
SharkBait said:
I thought you have tried the other power button by now? You don't even need another power button, just use a screw driver to short out the 2 pins where the power button connects and see if it stays on...?
Click to expand...

Wow, dude. Do I look like a cowboy to you? And if I contact the wrong pins? I guess theres no power, but still, I wouldnt risk it.

None the less, Im currently at work, will only get to try this these ideas out tonight.
 
DarkWhisperer said:
My PC was incredibly dusty and the fans were starting to grind. So I knew a spring cleaning was required. Im quite familiar with the inside of a PC, so I had no problems taking it apart, cleaning off the dust (gotta love canned air), and putting it all back together. However, on startup, the power comes on for about 2 seconds, and then goes off for about 4 seconds, then on again for 2 seconds, and then off, and round and round. So somethings wrong. Removed all uneccesary components like HDD's & graphics to try to get it to POST. But no luck. Tried using just 1 stick of RAM, and swapping those around, no luck. So either its my CPU or motherboard thats gone.

So the question is, which one is it and how do I tell? Can a motherboard power up and idle without a CPU? Is there something else I should be looking at, like my PSU perhaps?
Click to expand...

DarkWhisperer said:
Wow, dude. Do I look like a cowboy to you? And if I contact the wrong pins? I guess theres no power, but still, I wouldnt risk it.

None the less, Im currently at work, will only get to try this these ideas out tonight.
Click to expand...

Sorry, my mistake, I thought you knew which pins it is. :erm:
 
DarkWhisperer said:
Wow, dude. Do I look like a cowboy to you? And if I contact the wrong pins? I guess theres no power, but still, I wouldnt risk it.
Click to expand...
Its fairly safe. Just memorize the correct pins.

Plus his idea actually has a solid chance of being the cause.
 
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