How to clean up a Mac Pro cpu after delidding

Discussion in 'Mac Pro' started by Ashton1, Jan 30, 2019.

  1. Ashton1 macrumors newbie

    Joined:
    Jul 15, 2018
    Location:
    Chicago, IL
    #1
    Hi,
    I'm experimenting with de-lidding a pair of (5677) processors for a Mac Pro I have. I decided to experiment with the "vice method" on an old processor I had left over from another upgrade.
    The de lidding with the vice went really smoothly....the top seemed to slide over a bit at first and then with a soft pop, it just fell off.
    Now I'm unsure as to how to clean up the processor properly. I tried scraping off the solder with a plastic card, but it's not smooth.. If I used sandpaper or something I'm afraid I'd damage the pins around the edges?
    Any suggestions for what to do here?
    Thank you!
    20190130_delid_003.jpg 20190130_delid_006.jpg 20190130_delid_007.jpg 20190130_delid_008.jpg 20190130_delid_012.jpg
     
  2. Alaska_guy macrumors member

    Joined:
    Mar 30, 2018
    #2
    Use a credit card or some type of plastic scraper. Go easy. Just look up deliding processor for overclocking on youtube. Should get a bunch of hits.
     
  3. Slash-2CPU macrumors regular

    Joined:
    Dec 14, 2016
    Location:
    New Orleans, USA
    #3
    I used a new single-edge razor blade to remove the solder while holding the CPU in the vice. The CPU die is many times harder than the solder. The die sits up slightly higher than the capacitors. Keep the blade level on the die and it will clear the capacitors.

    You’ll still have very thin areas of solder on the CPU almost no matter what you do. It won’t have any real effect on cooling performance.

    I tried using a plastic spudger tool at first. The amount of force I was using, if it slipped, I would’ve easily knocked a capacitor off. Better to use an extremely sharp tool that shaves the solder off easily than a dull one you really have to push on.
     
  4. cdf macrumors regular

    Joined:
    Jul 27, 2012
    #4
    Interestingly, the next operation is actually the longest, but gets mentioned much less than the delidding:

    You should remove more material. First, take care of that black adhesive. Use your a rigid piece of plastic like an old credit card and isopropyl alcohol to clean it off as much as possible. You can also use your fingernails. Second, use masking tape to mask everything but the top of the die, which is covered in solder. Two layers of tape if you can. Third, use that old credit card to remove as much solder as you can. There is a surprisingly large amount on there. Then, use high grit sandpaper on a small sanding block and isopropyl alcohol to wet sand the surface. You will notice a slight change in color when you finally hit the die. Using the sandpaper, methodically get the entire surface like that. Finally, use very high grit sandpaper or a coffee filter to polish the surface. Remove the tape and throughly clean the CPU including the pads.
     
  5. gex85 macrumors newbie

    Joined:
    Dec 6, 2018
    #5
    I used a spare blade for a utility knife to scrape off the solder. I was surprised by the thinkness of the solder that had remained on the die after delidding. But ultimately almost all of it came off using just the blade. For the final touch I sanded the last bit of solder down with 2000 grit sandpaper. Covering the rest of the CPU in tape to prevent damage to the capacitors is a good idea, too.
     
  6. Slash-2CPU, Jan 31, 2019
    Last edited: Jan 31, 2019

    Slash-2CPU macrumors regular

    Joined:
    Dec 14, 2016
    Location:
    New Orleans, USA
    #6
    I’d argue that removing the black adhesive is functionally unnecessary and only risks damaging a capacitor. The glue sits lower than the CPU die, so it won’t unterfere with the heatsink. You’ll never see it once you mount the heatsink, so there’s not even an aesthetic reason.

    Get the solder shaved thin enough with a razor that you can see the silicon die through it, and you’re good. A layer of 0.02mm of solder won’t affect the CPU seating in the socket and it won’t affect thermal performance by any measurable amount.

    If you get satisfaction from having the die and substrate completely clean and neat, great. I get it. Perfection is nice. But it’s not necessary. ;)
     
  7. Alaska_guy macrumors member

    Joined:
    Mar 30, 2018
    #7
    I also agree, don't mess with the black silicon. It won't affect performance at all and it's going to be hidden. Your going for performance/function.
     
  8. h9826790 macrumors G4

    h9826790

    Joined:
    Apr 3, 2014
    Location:
    Hong Kong
    #8
    Those black silicon can affect cooling IF the user install the original plastic retainer back into position. (because the extra height increase the gap between heatsink and the die surface)

    Of course, it's much easier to remove the plastic retainer than those black silicon.
    --- Post Merged, Jan 31, 2019 ---
    Anyway, I think this is a good tool to remove the solder. Especially if the user has a vice to fix the CPU into position. Now you have two hands to keep the ruler parallel to the die surface, and apply slow gentle force by both hands.

    Not too shape, won't cut ourselves. But the edge it hard enough to remove the solder.
    image.png
     
  9. Slash-2CPU macrumors regular

    Joined:
    Dec 14, 2016
    Location:
    New Orleans, USA
    #9
    No, it’s really not a good tool. Try pushing on that with two hands. It’ll bend and flex like hell. It’s also got the same dull edge as a credit card. Dull edge means you have to push hard. When the solder gives, using two hands or not, the tip of the ruler is going to move quickly and with a lot of force. Catch one of the capacitors with it, CPU is dead. Thin, sharp razor will go through with many times less effort. Razor blade also won’t flex.

    I delidded two of them for my 12-core. Credit card didn’t work well. Neither did a plastic spudger. Razor went through it with a little more effort than butter.
     
  10. Alaska_guy macrumors member

    Joined:
    Mar 30, 2018
    #10
    I had a spare xeon laying around so I decided I would give the razor a try... It worked fine. To someone new to delidding with the solder... The best way I can describe it is the solder is going to be a softer metal than the actual chip. keep scraping away gently with light pressure. The solder will feel sticky. Once you get down to the actual chip you should be able to feel the difference between what is solder(sticky and soft) and the actual chip (harder metal).

    Slow and steady wins the race. Took me about 5 minutes start to finish on this chip.

    [​IMG]
     
  11. Ashton1 thread starter macrumors newbie

    Joined:
    Jul 15, 2018
    Location:
    Chicago, IL
    #11
    Ha! Yes, I agree...the actual de-lidding went super smoothly using the vise technique, removing the silver is the hardest part!
    --- Post Merged, Jan 31, 2019 ---
    Thanks all,
    I'm going to try the single edge razor and maybe very fine grit sandpaper if needed.
    I'll post my results later, but appreciate all the useful input.
     
  12. gex85 macrumors newbie

    Joined:
    Dec 6, 2018
    #12
    I think there's no point in leaving the black silicone (or whatever adhesive it may be) on the CPU. Using a utility knife or a razor blade it comes off super easy. No need to remove every tiny little trace of it, though. Like someone said above, leaving it on will prevent you from installing the plastic frame around the DIE, which imho is an important safety feature that can prevent severe damage to the DIE when mounting the cooler.
     
  13. Ashton1 thread starter macrumors newbie

    Joined:
    Jul 15, 2018
    Location:
    Chicago, IL
    #13
    I just completed the de-lidding and clean up and it went smoothly.
    Just used a single edge razor, slowly scraping away the solder. I ended up leaving the black rubber and it doesn't seem to have adversely affected anything.
     

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