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Motherboard and CPU Issues

By pt242 ·
i have a foxconn NF4K8MC-ERS motherboard and an AMD 64 4000+ cpu. when i removed the heasink from the cpu, the cpu was stuck to the bottom of the heatsink. this was done without releasing the cpu locking arm. now the board wont power on. which is most likely, the cpu or the mb being dead?

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by HAL 9000 Moderator In reply to Motherboard and CPU Issue ...

If it was working previously the most likely thing that has happened is that all the pins in the ZIF Socket got bent when you pulled the CPU out without releasing the socket so the CPU isn't actually making contact with all the pins.

I take it that you actually looked at the CPU and made sure that every pin was still on it though?


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by markjenkins74 In reply to Motherboard and CPU Issue ...


Did you re-apply Thermal compound paste when you re-installed the cpu? That's stucky stuff at the bottom of the heatsink, this must be re-applied everytime you remove and re-install your cpu and heatsink.


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by Nilt In reply to Motherboard and CPU Issue ...

Ouch. Sounds like the old compound was frozen and it yanked the pins out of the ZIF socket. It's always a good idea to loosen that arm first if you can, even if you can't get it to pop up all the way.

Make sure that you separate the heat sink and CPU, clean both with a small amount of rubbing alcohol on a clean lint free rag or chamois cloth and then reapply. Hopefully, as HAL indicated, you haven't actually yanked a pin off the CPU itself. If you're a novice at this sort of thing I'd recommend getting professional help unless you can afford to replace the whole board and/or CPU. It should take half an hour or so for a competent tech to get this resolved if it's not damaged beyond repair.

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by TheChas In reply to Motherboard and CPU Issue ...

I suspect that you will find that both the CPU and motherboard are damaged.

Even if you see no physical damage to the CPU itself, the forces transmitted through the leads when the CPU separated from the socket likely broke several wire bonds between the CPU die and the pins.

If you look at the bottom of the CPU with a high power microscope, you are apt to see fractures in the ceramic near some of the pins.

On the motherboard, even if there is no visible damage to the socket pins or fractured solder fillets on the board, it is VERY easy to fracture the vias that connect the pins to the inner layers of the circuit board.

The motherboard is a sandwich of at least 4 layers of copper circuits with fiberglass and epoxy between them. The connections between layers (vias) are very thin and fragile.

Since the risk of damage to a good CPU from a bad motherboard is high, I would personally replace both and chalk this up as a lesson learned.

Usually, thermal compound turns to glue only from age or extreme heat. Since an AMD 64 4000+ is not very old, it was likely running a bit hot. So, your CPU was more than likely getting close to toast anyway.


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by ozi Eagle In reply to Motherboard and CPU Issue ...

A note about AMD processors and heat. There is no protection in the CPU for overheating, though mobos do have thermal protection. Running the cpu without effective cooling can cause the innards to fuse.

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