How to remove a very stubborn heatsink from a CPU

3

While replacing a heatsink I accidentally pulled out the CPU with it. And after two days of trying various tips I found online it's still stuck on there.

And of course I can't put it back into the mainboard because of the socket locking mechanism.

The CPU is an AMD Phenom II X6 1100T. I'm not sure what was used as a thermal conductor. I was thinking that normal thermal grease could never glue it together like that. But then again I'm not sure what the stock thermal compound does when burnt in 24/7 for basically 4 years. (The PC is used for scientific calculations)

So I'm at the point where I think it's almost inevitable to replace the CPU but maybe someone has got an idea.

What I've tried:

  • Trying to twist the CPU off. It won't budge and there is not a lot of surface to work with.
  • Using Isopropyl alcohol on cotton swaps to clean off excess thermal paste. This worked OK.
  • Using dental floss to try to get between CPU and heatsink. No chance.
  • Heating the heatsink with a hairdryer and trying to twist it off. No change here, except it was indeed very hot and harder to handle
  • Soaking it completely in Isopropyl for 24 hours, heating again. No luck.
  • Using a box cutting knife to try to get between the CPU and heatsink. I managed to scratch and make a few notches in the copper of the heatsink where it meets the CPU heat spreader. But it's not going anywhere.
  • Using a small pair of pliers to twist the CPU off. It has a few more scratches now on the sides of the integrated heat spreader but wouldn't budge.

Further ideas:

  • Buying/borrowing a heat gun and trying to use this to soften the thermal grease/glue(?). But I'm not really sure where I would apply it without damaging the CPU or loosening the CPU PCB from the heat spreader.
  • Using acetone to loosen the glue. I think the CPU is not really gonna like that. And it might be difficult/impossible to apply it only to the area between CPU/heatsink.
  • I might have access to other solvents commonly used in chemical laboratories. But I don't know If they could get between the CPU and heatsink or if there just is not enough of a gap.
  • As a last resort using a fine metal saw to separate the CPU... This will probably work, but how am I ever going to get a good thermal coupling again? I would need to sand and polish the top of the CPU heat spreader. Not the best option, but I'm almost out of better ideas.

BubuIIC

Posted 2015-08-21T18:24:42.847

Reputation: 546

That is very strange. – Keltari – 2015-08-21T18:28:08.833

Answers

1

It must be a thermal adhesive, not thermal grease. Whenever I’ve removed heatsinks with an old application of thermal grease, the stuff is generally a bit dried out looking and the heatsink becomes easier to remove, not harder. It could be something like Arctic Silver Thermal Adhesive.

You’ve tried most of the things that I’ve seen recommended, except freezing it. Some say that freezing it can make the adhesive more brittle. Not sure how effective this will be since I’ve never tried it, but at least it’s something you could try.

user5071535

Posted 2015-08-21T18:24:42.847

Reputation: 380

Probably an adhesive. (It might be noted that Arctiv Silver writes 'Never apply this to a CPU' in big letters, but...) I will try freezing it. If it does not work with the standard -18°C at what point would it pose a danger to the CPU? Would -50°C be still OK? Liquid Nitrogen? (~-195°C) – BubuIIC – 2015-08-21T18:57:11.640

2Be sure to put it in an airtight plastic bag – Keltari – 2015-08-21T19:02:33.147

2If somebody did use a product like Artic Silver you probably don't have a lot of good options. Solvents that will disolve it may also attack the chip. Freezing may work to separate dissimilar materials . The cold, itself, wouldn't hurt the CPU, but something like liquid nitrogen is likely to make it brittle, so it could break if you apply force to separate it. If freezing, alone doesn't pop them apart, try freezing and going immediately to an oven at maybe 200 degrees F. The metal in the heatsink will expand faster than the plastic and that may do it. – fixer1234 – 2015-08-21T19:14:04.273

Once they are apart, you will probably need to grind the adhesive off the CPU, although once it is exposed, you could experiment with solvents. – fixer1234 – 2015-08-21T19:14:27.453

1@BubuIIC Not sure what the lowest safe temperature is, but you should try looking up the CPU's specifications. You may be able to find it in the CPU's datasheet if you can get it from AMD. I think the spec you'll want to look for is the minimum storage temperature, not the minimum operating temperature. – user5071535 – 2015-08-21T19:16:48.073

Asked: 2015-08-21T18:24:42.847

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Active: 2015-08-21T19:00:06.243