Solved Dead CPU/mobo?

Hey all,

So I finished installing my water cooling setup (which works fine), but now my computer won't start up.
The PSU provides power, the fans spin, LEDs light up, etc, but the computer does not post. No beeps, nothing.

I suspect that I might have fried the CPU or motherboard...
Can someone confirm, or (even better) tell me it isn't and I just missed a plug?

I have tried:
Resetting BIOS (doesn't get there anyways)
Swapping/removing RAM
Removing PCI (and GPU) cards

I really hope someone can tell me what is going on... Even if it is just to confirm an expensive mistake...

~Lordbob

Did you use a ground strap to keep the static eletricity away, didn't knock any wires loose on mb, hdd, etc. I'm hoping for the best

1Bowtie said:

Did you use a ground strap to keep the static eletricity away, didn't knock any wires loose on mb, hdd, etc. I'm hoping for the best

Click to expand...

I was touching the case the whole time I was working with any components.

I did pull the CPU out of the socket to get it a little cleaner, but again, was touching the case while doing so...

~Lordbob

I'm looking at your mobo at Asus. You don't have any of the lights on the board like some of the newer ones it appears.

Check list of what you may not have checked. Just possibilities.
Did you recheck the Q connector if you are using it? They come loose very easy.

CPU cooler mounting bracket on the back of the moboard insulated properly? I'm assuming it has one. Some don't. Dead short if it is touching.

The obvious power connectors on the board which I'm sure you rechecked three or four times by now.

If you pulled the CPU you could have bent a pin on reinstall on moboard. Or not seated on the pins properly.
Possibly fixable if you can see a bent one with magnifying glass.
Tweezers maybe. Something plastic. Better yet Bamboo Barbeque skewer.
Maybe.

I'll add when I think of something.

Hello,

I'm not a hardware guy but I could suggest something. Remove the CMOS battery and start the PC and shut down the PC put it back and see if that fixes it. Remove all the RAM and see if you have a Memory beep.

- Captain

My roommate and I just fixed a bent pin on the CPU, but still no post.

I already tried resetting the BIOS.

~Lordbob

It is possible it damaged the CPU. Broke the connections inside.

I actually was hoping I was wrong about the bent pin.

Hopalong X said:

It is possible it damaged the CPU. Broke the connections inside.

I actually was hoping I was wrong about the bent pin.

Click to expand...

To be completely honest, I suspect it has been bent/broke for a while.

My roommate and I are leaning heavily towards a bad motherboard, because of no power to USB, and no post.

~Lordbob

When working on a problem build it is always best to strip everything down to the bare motherboard. I set it on an anti-static surface (the bag it came in) and arrange the case and power supply close enough to make the basic connections. You do not need to make the case connections at this time. Use a screwdriver to cross the two PWR pins to turn it on when needed. But if I can I hook them up.

Turn on the power supply and turn on the motherboard. Without a CPU nothing will happen, but you do want want to see that green light come on showing the board is getting power. Then add the components one at a time.

When you install the CPU and start you should get an error beep code: no RAM. This is Good.

Add ONE stick of RAM and start. Error beep: No video.
Add more RAM.

Then the video card and monitor. Keyboard (use PS2 for troubleshooting).

If at any point you do not get the expected result you know the prior part is the fault and can work from there. Any time after the RAM test you can put everything back in the case. The reason for out of the case is to eliminate standoff shorting as a cause.

Very rarely is a CPU bad and it takes effort to kill one. Most times a dead rig is a motherboard issue. As a last resort you can try a CLRTC.

The power supply is key. The motherboard has lots of logic circuits and if there is any issue with the power supply it can cause the board to cut out. Use a spare supply to test with, even if it is underpowered for the rig. You don't want to run a full system on it, just those first few crucial components.

Let us know how the process goes.

This just occurred to me. You are water cooling. A motherboard will not boot without a heatsink/CPUfan connected. Did the watercool kit anticipate that?
You could just plug the fan into the CPU header and hold it to test. I think there is a BIOS setting to turn off the fan check.

TVeblen said:

This just occurred to me. You are water cooling. A motherboard will not boot without a heatsink/CPUfan connected. Did the watercool kit anticipate that?
You could just plug the fan into the CPU header and hold it to test. I think there is a BIOS setting to turn off the fan check.

Click to expand...

I have a bad habit of posting a quick answer before reading the whole thread through, but that is exactly what I would have said had I not restrained myself. Nice call, and for Lordbob's sake I hope you nailed it.

TVeblen said:

I set it on an anti-static surface (the bag it came in)

Click to expand...

For future reference, that is actually a bad idea as the outside of the bag is conductive. The anti-static bag is only non-conductive on the inside of the bag.

Placing it on a non-conductive surface like the cardboard mobo box is a safer option.



****
Dennis,

As Tvblen suggested, remove the board from the case and strip it down to bare components. Basically CPU only.

Remove the waterblock/mounting kit if you haven't already.

Reseat the CPU and install the stock HSF if you still have it. (don't worry about replacing the thermal paste - you won't be running it long enough for it to be an issue)

Double check that you have the 24pin (mobo) and the 4/8pin (CPU) plugs firmly connected.

If it's still dead in the water - you have borked the mobo.

If it springs to life, then the issue is elsewhere (not mobo or CPU)

Guys: Thank you for all the suggestions.
I have tried most of this so far, but I have yet to strip everything and test it individually.

I have pizza, drinks, and a few spare hours to sit and troubleshoot this.

~Lordbob

Holy shit I got a beep code. Thank you TVeblen for the recommendation to take it all apart.

I think the problem was a bad pin (again). There was one little one in the socket that was slightly bent over, so we unbent it and made it straight (enough). There was still no Post however. Now that I took it out again, I think the pin next to it was bent downwards, so I bent it back up (read: spent 15 minutes trying to actually touch it with my tweezers).

Anyways, I am going to go through one thing at a time until I get posting.
Thank you all so much for your help (and saving me like $300).

~Lordbob

OK, it all works now

Thanks for all the help guys.

~Lordbob

Glad to hear you got it running.

Did you identify what was causing the issue?

Inquiring minds want to know...

I presume the bent CPU socket pins were not making pad contact to the CPU = no go.

Bending the socket pins back in place to contact the pads = go

Excellent. What did I tell you. That sounds tacky.
I'm not gloating just glad you found the problem and fixed it.
Sorry you had the problem but glad you got her fixed.

P4's are notorious for bent pins . You have to be SUPER careful on alignment and seating.

Mike


Smartyeyeball

Yes they have pins and a pad.
Bottom pic left side is CPU each gold piece standing up is a pin that matches the pad on the motherboard side in right side of pic. Very delicate. The pic is double actual size at least.

Way to go Lordbob glad all went well

Hopalong X said:

Smartyeyeball

Yes they have pins and a pad.
Bottom pic left side is CPU each gold piece standing up is a pin that matches the pad on the motherboard side in right side of pic. Very delicate. The pic is double actual size at least.

Click to expand...

True to a point mate.

Older sockets and AMD chips still have physical CPU pins, however intel 775 > only have contact pads on the CPU (no physical CPU pins). The pins are only in the motherboard socket.

Still bloody delicate though