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  • IC pad greyed out

    Hi

    This is a iPhone 6 CPU and the IC has some greyed out pads. How can i restore those pads that are too grey? In this state the solder won't suck on.
    - Flux and some tin do not do the trick
    - Solder wick and heat also don't do the trick
    - Isopropyl won't help either

    I really don't want to scratch away this "layer" to get to the shiny pad.
    Attached Files
    Last edited by GuruFix; 02-05-2020, 03:49 PM.

  • #2
    Those look more like missing pads than oxidized pads.

    Comment


    • #3
      It look like it but they aren't. Scratched away the grey layer and it looks shiny again! I got these pads also at the PCB side.
      Unfortunately i wicked too much or too much heat because now the top layer is damaged.

      Can you tell me how you clean a CPU step by step from start to finish please?
      Attached Files

      Comment


      • #4
        I don't put any braid on CPU. I will braid CPU pads on the board.

        This CPU does not look normal--it looks like maybe missing pads and second layer trace is tinned now. Too hard to tell from a photo.

        iPhone 6 CPU should be green--with 100% of underfill removed from CPU.

        I use a low melt paste to make the solder low melt on CPU, then heat at 200C and gently scrape underfill from chip. Gray pads will turn shiny with the paste. At the end, the chip is very flat--there are no depressions like missing pads.

        Comment


        • Jessa_the_Professa
          Jessa_the_Professa commented
          Editing a comment
          and by gray pads--i mean light gray. Like elephant ears. Not dark gray like missing pads
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