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need some CPU/heat sink service advice

PostPosted: Mon Jan 25, 2010 2:01 pm
by MrFredPFL
i've got an old (celeron, i think) CPU i need to move to a replacement motherboard. the problem is that the CPU feels like it was welded to the heat sink. without removing it from the heatsink, there's no way to unlatch the CPU socket on the replacement board, as the heat sink is above the lock lever, making it totally inaccessible. how do i separate the CPU from the heatsink without using a crowbar?

Re: need some CPU/heat sink service advice

PostPosted: Mon Jan 25, 2010 2:27 pm
by IneptVagrant
You don't.

The old board is trash I'm assuming, just go at it with a flat head screw driver, and a hammer or something till the bond breaks. Use the screw driver as a wedge and apply extreme violence.

Then clean up the surviver (assuming there is one) with acetone or isopropyl

Re: need some CPU/heat sink service advice

PostPosted: Mon Jan 25, 2010 2:36 pm
by MrFredPFL
errrrr, lol, i think something may have lost in the translation. yes, the old motherboard is trash. but it is no longer a part of the equation. i unscrewed the heatsink from the old MB, no problem, and it came right off, with the CPU tagging along. this is interesting, since it must have just pulled the pins out of the locked socket. in any case, the heatsink and CPU came off as a unit. now, my problem is that i need to put this cpu on the replacement board, which i assume i can't do till i separate the heatsink first ;)

Re: need some CPU/heat sink service advice

PostPosted: Mon Jan 25, 2010 3:14 pm
by bmh67wa
Heat up the whole assembly with a hair dryer until the paste softens. It will usually come right off. In extreme cases I have had to use fishing line as a saw across the edges of the processor while heating it up. I have also seen people use a small screwdriver to pry with success but that method always scared me!

Re: need some CPU/heat sink service advice

PostPosted: Mon Jan 25, 2010 3:38 pm
by MrFredPFL
:lol:

+1on the screwdriver thing. i thought about that and dismissed it instantly :o

i have heard about a hair dryer. is this safe? no static issues, especially in the winter?

Re: need some CPU/heat sink service advice

PostPosted: Mon Jan 25, 2010 5:37 pm
by bmh67wa
Well, a torch would heat it up too without static problems. :lol:

Re: need some CPU/heat sink service advice

PostPosted: Mon Jan 25, 2010 9:08 pm
by nifty
If you keep the motherboard plugged into the power supply, and the power supply plugged into the wall, but keep the wall socket switched off, then the motherboard will be grounded safely, and you don't have to worry about static.

Re: need some CPU/heat sink service advice

PostPosted: Mon Jan 25, 2010 9:48 pm
by MrFredPFL
thanks to all :toast:

the beast is off. good thing a friend left his acetylene torch here, although i really should have used it outside. :!:

Re: need some CPU/heat sink service advice

PostPosted: Tue Jan 26, 2010 1:28 am
by MrFredPFL
and the cloned machine is alive and well. thanks again :)

Re: need some CPU/heat sink service advice

PostPosted: Tue Jan 26, 2010 8:29 am
by HouseCrowd
MrFredPFL wrote::lol:

+1on the screwdriver thing. i thought about that and dismissed it instantly :o

i have heard about a hair dryer. is this safe? no static issues, especially in the winter?


CPUs are usually surprisingly tough.

I've successfully prised stuck ones off with a screwdriver before, though that's not my preferred method either. There is a risk that you could chip a piece off the edge that way - though even if you did, it probably wouldn't harm the silicon die within, so the damage would be largely cosmetic.

I find the best way is to hold the heatsink and CPU sideways-up, then find something flat and solid to use as a sort of drift to place against the edge of the CPU. Then a few light taps of the drift with a hammer, and the CPU will usually fall off.

Re: need some CPU/heat sink service advice

PostPosted: Tue Jan 26, 2010 11:22 am
by MrFredPFL
I find the best way is to hold the heatsink and CPU sideways-up, then find something flat and solid to use as a sort of drift to place against the edge of the CPU. Then a few light taps of the drift with a hammer, and the CPU will usually fall off.


hehe. rule one of field service work:

There is no problem so complex that it cannot be solved by brute strength and ignorance. :D

Re: need some CPU/heat sink service advice

PostPosted: Tue Jan 26, 2010 11:40 am
by sunnyd
Good thing you did not need to apply rule 6 because there isn't one. :)

Re: need some CPU/heat sink service advice

PostPosted: Tue Jan 26, 2010 11:46 am
by MrFredPFL
Bruce wrote:Good thing you did not need to apply rule 6 because there isn't one. :)


true dat!

this here's the wattle
it's the symbol of our land
you can stick it in a bottle
you can hold it in your hand

Link: http://www.youtube.com/watch?v=_f_p0CgPeyA

Re: need some CPU/heat sink service advice

PostPosted: Tue Jan 26, 2010 5:54 pm
by bmh67wa
MrFredPFL wrote: good thing a friend left his acetylene torch here, although i really should have used it outside. :!:


On the kitchen table didja?


Another who still appreciates the power of fire. Did the exact same thing a few years ago but whenever I mention it people think I'm crazy. I'm too impatient to use a hair dryer though I have seen it done successfully by others.


Actually I am crazy but for other reasons not related. :lol:

Re: need some CPU/heat sink service advice

PostPosted: Tue Jan 26, 2010 11:31 pm
by sunnyd
Lol, I had always heard about the Monty "no rule 6" (enough to repeat it myself), but I never actually saw the skit, I just watched it (thanks for adding that YouTube post Fred), now I know why it was so funny. :) I did say in the current alphabet game that I did not watch much Monty Python, but Google and YouTube are helping until we get to Z, thankfully, or HC would have been playing that one mostly by himself, lol.

Re: need some CPU/heat sink service advice

PostPosted: Wed May 12, 2010 2:02 pm
by freakytiki4u
I have a P4 CPU that the actual heat sink of the CPU came off. So I have the green CPU and the cooler that is usually bonded to it that are now separate. What would you suggest I use to glue them back together. Just so I'm clear, this is not the normal large heat sink you clip down onto the CPU, I'm talking about the cooler under that one that is usually bonded to the top of the actual CPU. I have never had one separate on me like that before. lol

Re: need some CPU/heat sink service advice

PostPosted: Wed May 12, 2010 2:20 pm
by MrFredPFL
you need thermal paste. it won't glue them together, per se. what appears to be glue from the original setup is the old thermal paste which has been baked into its current consistency. clean off as much of it as you can. i was told rubbing alcohol would remove it, but my experience told me that was a less than ideal solution. my suggestion would be to take all proper precautions against static, and use a fingernail to scrape the stuff off. then replace with fresh stuff, and reassemble.