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Ultrasonic breaking boards?

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  • Ultrasonic breaking boards?

    I'm a noob at doing MacBook board repairs, it's pretty much a hobby at this point (I buy dead units on eBay and attempt to fix them as practice). I attended Jessa's class and outfitted my bench with tools recommended by Louis and Jessa. This includes a Crest ultrasonic unit. I must be doing something wrong, as about 1 out of every 5-7 boards goes in working (after I fixed them) and comes out not working. I haven't really taken the time yet to troubleshoot those at this point, I'm generally too frustrated and set them aside.

    Here's my process:
    -8 minutes at 50 deg C
    -Lightly scrub the boards with a toothbrush while sitting in 99.9% isopropyl alcohol
    -Drip dry for a few minutes (length of time depends upon my patience level at the moment)
    -Use canned air or hot air station to gently dry the board off
    -Install back into the chassis

    Does anyone have a "best practices" list for proper ultrasonic usage?

    As best I can tell, I am not dislodging components with the toothbrush. I wonder if it's moisture inside a shielded area that hasn't fully dried when voltage is applied?

    Thanks in advance!

  • #2
    You're not drying the boards long enough. I usually put it in the cleaner 2 minutes on both sides at 65 celsius, brush it with alcohol, use air compressor to blow out alcohol from under the CPU, SMC and other big BGAs then use heat to dry it. Most recommend a small oven for about 30 minutes.

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    • #3
      Oh my! I guess I should consider myself lucky with the ones that I DIDN'T have issues with. Thanks so much for the reply. What is a safe oven temperature? I'm assuming a small toaster over will do the trick (as long as it's wide enough for the boards)?

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      • #4
        Not totally sure as I don’t use one. I use my Quick to dry them. I use the Quick with no nozzle at 280 Celsius. If you do this method, NEVER EVER put air directly on the CPU

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        • #5
          Thanks for the advice John, it was very helpful.

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          • #6
            Ultrasonic @ 65C with Branson ES, 6 minutes a side. Alcohol bath for a few minutes. Blown dry with air compressor on regulator, and sit on my iPad heat pad @ 65C for 20 minutes with a towel or rag over it. Always dry as a bone.

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            • #7
              I don't use a ultrasonic cleaner. I use a water pick! I think ultra sonic cleaners are over rated. The water pick really blasts under BGA chips! I use a vinegar / soap solution with a micro fiber glass brush on the bad areas. Let that sit for a while then use a water pick with soap and water then rise with fresh water. Then I use compressed air and I am done. The board is in and out and back in in a few minutes.

              No risk from a ultra sonic cleaner damaging boards, it is faster. and it didn't cost $1000 dollars.
              Last edited by KC Micro Tronix; 11-01-2019, 07:50 PM.

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              • #8
                I use a Sharpertek UC, 2 min each side in Branson EC @ 65C, rinse in 99% IPA for 3-5 min, into toaster oven for 30-60 min @ 200 F = Never have non working board after 50
                + machines. In fact, it has fixed 4 that I couldn't!

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