Any ideas to remove glued on heatsinks

[warrensgun]

So I was able to get some replacement X3 boards from MS (thank you), and I am going to just move the heat sink from the dead one to the good one.

The heatsink for the asic is held on by 4 screws - simple enough.  On either end of the board is another heat sink and that one is applied with some type of glue, I tried pulling, turning, twisting, etc, but I don't really want to accidentally break the defective board in the process of removing the heatsink.  

I have a heat gun I could try to heat them up, but I didn't want to go too hot and melt anything.  




Replacement board


Any tips

[TheRealSteve]

Heating it up is probably going to be your best bet - remember, they're intended to deal with rather hot chips in the first place, warming it up a bit isn't going to hurt much.

One other thing you could try, though, is fishing wire or any other thin but strong wire, and see if you can get that between the heat sink and the surface, then just 'saw' through.  It's sometimes used in garages to remove worn/damaged badges from cars without damaging the coating on the car; the glue they use is pure evil.
https://www.ifixit.com/Guide/Debadging+a+Car/7299

[Bicknellski]

http://www.overclock.net/t/1231696/how-do-i-remove-heat-sinks-that-are-bonded-with-a-thermal-adhesive

Google foo. Do it at your own risk obviously.

https://www.youtube.com/watch?v=f9cQ1PbXzuo Video removal.

[warrensgun]

I had googled it, and some of the results didn't sound the best.  This is stuck to 12 chips.  So it's not like a little heatsink stuck to a single chip. 

I tried to heat it up by leaving it behind a working X3, figuring maybe that owuld be hot enough, but that didn't work.  I'll try the heat gun today - I just didn't want to melt the board.

[bbeesley]

since the thermal paste isn't an adhesive, I am betting that most of the strength in the bond is from vacuum which can be pretty significant.

it isn't going to have much shear strength so sliding or twisting should break the bond.

warming it is going to be challenging because the heat sink is designed to radiate the heat away from the chip itself.  You are going to need a pretty decent heat gun to overcome this.

[Bicknellski]

If you get pure isopropyl you can just submerge the whole thing, lift it out, twist, and it should come off nice and easily (well, along with the silkscreens and stickers on the PCB, but thats okay,  )

The pure isopropyl bath then horizontal sheering twist?

I don't envy you having to do this. Seems monumentally hard.

[warrensgun]

heat gun gets hot enough to light paper on fire - it's just a normal heat gun, but then you can't touch the heat sink....
It isn't just thermal paste, they are actually glued on - per MS

I finally got them off of one board by applying some heat, sideways twist and then finally putting a pair of pliers on it and prying up.

Now to get the white blubbery gunk off the heat sink... Then repeat the process a few more time.s

[Bicknellski]

heat gun gets hot enough to light paper on fire - it's just a normal heat gun, but then you can't touch the heat sink....
It isn't just thermal paste, they are actually glued on - per MS

I finally got them off of one board by applying some heat, sideways twist and then finally putting a pair of pliers on it and prying up.

Now to get the white blubbery gunk off the heat sink... Then repeat the process a few more time.s

Pictures... video?

Be a good idea for others to have later that could go through same issues.

[richardamullens]

When you discover what will remove the glue, let us know.

I'd try d-limonene to start with, then methylene dichloride then MEK.

[warrensgun]

I was able to get them off by applying rubbing alcohol where i could see the white blubber, twisting as much as I could, and then finally I'd put a pair of pliers on the heat sink and kind of pry it off. 

On one of the boards admittedly one of those R22 things broke off the board as well.  Since I figured that they are more concerned with getting chips back, repairing an R22 if the needed to isn't a big deal.

So Perhaps some other manufacturers will take this into consideration - if you need a large heat sink to cover 8 chips - GLUE is a bad idea (backed up by yellow scotch tape) (Off topic: why is so much tape out of china yellow...).  Instead the heatsink should have been screwed or pressure clamped on.  In an ideal world it would have been 1 heatsink per board, not 4.  (1 per chip, 1 per side for the power things)

I ended up scraping the glue and crap off.  MS suggested 99% ISO alcohol to help remove the gunk.  I didn't have any handy, so I used a knife and some 70% iso.  Afterwards I sanded the bottom of it with some fine grain sand paper (hope thats ok) to smooth out the surface.

After everything was cleaned up I gave it a final wipe with alcohol and sprayed the small bits of dust off with canned air.

Next one I do I'll try to take a few more pictures with some better lighting. 

All in all it's about an hour project by the time you pull the machine from service, figure out the bad card, remove the screws, etc.