1
\$\begingroup\$

I am modding a wireless router, and one of the problems I have is that it overheats, so it restarts every hour or so I am trying to replace the heatsink.

However, I simply cannot get it off. It seems to be glued on to the board or something, or they have used awful thermal paste! I have tried using a flathead to lever it off and scrape the paste away, but it is solid, and is impossible to remove.

Here are some images (sorry about my terrible photography!): White Paste Top view

So, how can I remove a stuck heatsink? I don't really feel comfortable using heat guns or trying to melt it off, as I am worried that I will cause damage to the PCB.

The processor is soldered to the board as well, so I can't remove it and work it loose by pulling it apart by hand either.

\$\endgroup\$
5
  • 6
    \$\begingroup\$ Instead of trying to subtract the heat sink, Why not just add a fan? \$\endgroup\$
    – EM Fields
    Aug 9, 2014 at 0:23
  • 3
    \$\begingroup\$ It sounds like you've already spent more time on this than it's worth. This type of device really isn't meant to be repaired. Just bin it and get a new one. \$\endgroup\$
    – Dave Tweed
    Aug 9, 2014 at 1:04
  • \$\begingroup\$ I dont really want to throw it away! Mainly as other people have got it off - i.sstatic.net/3twnQ.jpg \$\endgroup\$
    – George
    Aug 9, 2014 at 1:37
  • 2
    \$\begingroup\$ Adding the fan first will tell you if its a cooling problem to begin with. If you add a fan and it still restarts, you will have saved yourself a battle. \$\endgroup\$
    – dext0rb
    Aug 9, 2014 at 3:03
  • \$\begingroup\$ I'll try adding a fan and see if that works out. Thanks :) \$\endgroup\$
    – George
    Aug 9, 2014 at 12:23

3 Answers 3

5
\$\begingroup\$

To assist in removing heatsinks that are held in place with thermal glue, turn unit on, until the heatsink gets to its (typically) very high operating temperature. After unplugging all power to the unit, gently try twisting the heatsink, and rock it away from the i.c.; the additional heat will help soften the thermal (glue) paste. This info came directly from one of the manufacturers of thermal glue - used to hold heatsinks in place on high end video cards.

\$\endgroup\$
1
  • \$\begingroup\$ Thanks. I'll give this a go and then mark it as an answer if it works \$\endgroup\$
    – George
    Aug 9, 2014 at 12:27
1
\$\begingroup\$

I managed to get it off.

NOTE: I used MINIMAL force when doing this. Using an excessive amount of force could do all sorts of damage as @passerby has mentioned!

What I did is used a 1.0mm Watchmakers' Screwdriver, and forced it in the small gap between the heatsink and the CPU. Then I got a small allan key multi tool and started tapping on the end of the screwdriver. Then it just popped away!

\$\endgroup\$
3
  • \$\begingroup\$ This is not a proper way to remove a heatsink. This leads to a lot of torque on the IC it is attached to, and can cause pins or worse, bga balls to break or detach from the solder and pcb, or internal damage to ic wiring. \$\endgroup\$
    – Passerby
    Aug 9, 2014 at 19:20
  • \$\begingroup\$ Well, I suppose its not as bad as trying to lever it off with a screwdriver! I'm useless at electronics! \$\endgroup\$
    – George
    Aug 9, 2014 at 21:22
  • 4
    \$\begingroup\$ @GeorgeH It is trying to lever it off with a screwdriver. Just a smaller one. \$\endgroup\$
    – user207421
    Aug 10, 2014 at 0:42
-1
\$\begingroup\$

Looking at all the elyts on the board... they're not visibly leaky, but I'd still try replacing them with cheap solid-poly or high-capacity MLCC. Sometimes this helps (certainly when the elyts are already bulging/leaky).

As for thermals... the heatsink is typically too small, and the enclosure is airtight. Try drilling some holes in the plastic to give the heatsink a chance to breathe fresh air. Try drilling the holes such that you encourage free convection, i.e. you need a pack of holes over the heatsink and another set in other places around the plastic enclosure.

\$\endgroup\$
4
  • 2
    \$\begingroup\$ How does this answer the question about removing the heat sink? \$\endgroup\$
    – pipe
    Nov 30, 2017 at 9:26
  • \$\begingroup\$ @pipe: You're right. But it does propose additional/alternative measures to bring a freezing gadget back to normal life, possibly without trying to rip its heart out :-) \$\endgroup\$
    – frr
    Nov 30, 2017 at 10:43
  • 1
    \$\begingroup\$ Yes, but removing heat sinks fastened with thermal glue is a relevant question. People searching on that subject will end up on this question and expect an answer to that question. If you think the user has an XY-problem, it may be better to ask about that in a comment. \$\endgroup\$
    – pipe
    Nov 30, 2017 at 10:47
  • \$\begingroup\$ Okay, you're right... I myself have come to this topic while searching for how to remove a heatsink. Because yes a bigger heatsink is due, in my case :-( Thanks for explaining the rules for me. \$\endgroup\$
    – frr
    Nov 30, 2017 at 14:07

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.