stuck cpu heat sink

[Peaceful]

I run across this from time to time, wondering how others handle it.
Got an old compaq in bad need of an internal cleaning. I can't get the heat sink to seperate for nothing. I tried powering on minus the cooling fan hoping to soften up the thermal compound but it just would not break loose. Finally after
pulling and tugging the whole deal pulled out of the socket, and have no way
to get the cpu back in the socket because it's still seized to the heat sink.
I'm afraid to pry on it too much as I'm sure I'd just end up destroying the cpu.

Anybody know any tricks?

 

[16k_zx81]

you need to twist instead of pulling

Twisting will break the seal. Pulling will just remove the cpu from the socket.

If you cant do this, slide a plain stanley knife blade between the HS and the CPU (ie not in the knife enclosure, just the blade itself)

 

[NYJimbo]

Dry paste has a powerful bond between the two surfaces, especially with the broad flat surfaces on P4 chips.

However if you pry one corner or corner edge you will force a peel or shear which works better because the bond is much weaker to that force and the moment it begins to give, the shock from the break will "peel" the whole chip at once from the heatsink. I usually use a thick flat head screw driver near a corner but not directly on the point of the corner.

Hope that made some sense.

 

[Rob_NNCC]

I will take the deal to the edge of my work bench. I put the side of the CPU on the bench with the pins facing the stuff on the bench then push down on the heatsink. If you are careful not to let the CPU slide off of the edge and bend the pins it works well.

I have seen CPUs ruined using the pry method because the bond holding the speader to the heatsink was stronger than the spreader to the fiberglass board the die is on.

 

[16k_zx81]

I had a work experience guy here a couple of weeks ago

He couldnt get 775 CPU off HS so squeezed the sides of the CPU with his finger and wrenched - bending two columns of pins.

30 mins later and a lot of time spent with some fine tools and a large magnifying lamp and I managed to get them straightened and the CPU back in the socket.



..

 

[Peaceful]

Wierdest thing, went back at it the next morning with a flathead screwdriver, and it came off without much effort at all.

 

[SuGz]

What you want to do in this situation is to buy a heat gun and apply heat on the heat sink not to long just enough so the paste gets softer usually it will just slide off or just come off easier. I tried to pull a CPU off a heat sink without the heat gun and i damaged the pins. DO NOT APPLY THE HEAT FOR TOO LONG just try to keep it away from the heat sink try not to apply to close.

 

[mraikes]

Dry paste has a powerful bond between the two surfaces, especially with the broad flat surfaces on P4 chips.

However if you pry one corner or corner edge you will force a peel or shear which works better because the bond is much weaker to that force and the moment it begins to give, the shock from the break will "peel" the whole chip at once from the heatsink. I usually use a thick flat head screw driver near a corner but not directly on the point of the corner.

Hope that made some sense.

^^^ This. I do it all the time with the older seized processors. Doesn't seem like you should pry away with a screwdriver like that (fear of breakage and all) but I've never broken one and it's always worked.

 

[jbartlett323]

I usually just pull it from the socket on pinned sockets (on LGA sockets, its a bit harder. just gotta twist+pull the sink off). Then use the back side of my pocket knife under the edge of the proc, so the back of the blade spans one whole side of the proc. Give the knife a twist, and it pops right off. Done this a million times, haven't hurt one yet...

 

[The Tech Professor]

I replaced a clients motherboard the other day and when I removed the heat sink from the original mobo it came out in one piece, processor and all! The Pentium 4 processor was incredibly stuck to the heat sink/fan as if they were actually one solid unit.

The previous builder had used cheap thermal paste, applied too much, and now I had a mess on my hands. I have never seen a processor so “welded onto” a heat sink!

I tried a hair dryer at first for over half an hour (five minutes or so at a time) but I couldn’t pry the processor loose. The heat sink got good and hot (to soften the thermal compound), and I was trying to twist the processor off with my hands but “no go”. This processor could not simply be twisted off and since I had to use it again I had to be careful not to bend any pins by forcing. I decided to try something else.

I went and bought a bottle of 91% Isopropyl Alcohol and spent at least half an hour dabbing all four sides of the processor (where it joined the heat sink) using various Q-tips soaked in the Isopropyl. I then took a single edge razor blade and forced it into a tiny crack between the processor and heat sink.

With much force, the processor popped off and I only had a couple of scratches on the heat sink. I sanded these scratches down (fine sand paper) until smooth, applied a small amount of fresh thermal paste to the processor and put the processor and heat sink on the new system board.

The CPU went in “without a hitch” and the unit is running fine and much cooler than before.

I would also like to add that when I was originally removing some of the thermal paste (it was glued solid under the processor but oozing out the sides), some of the paste got on to several of the processor pins.

I took a soft bristle flat toothbrush, dipped the toothbrush in the Isopropyl Alcohol, shook out the excess Isopropyl Alcohol, and gently brushed the processor pins (in the direction of the pins). The thermal compound came out (dissolved) no problem!

Best wishes,
The Tech Professor

 

[Boston Pro Comp Serv LLC]

Heat gun on low, or twist it.