Removing DAC Chips?

Discussion in 'DIY' started by Luckbad, Jun 8, 2017.

  1. Luckbad

    Luckbad Basshead - Friend

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    I have two MHDT Labs Pagoda boards, both with a blown DAC chip (PCM1704). Apparently they had a crappy supplier for a while and switched after this happened several times.

    I'd like to replace the chips so I can have at least one functional board.

    Has anyone ever removed a DAC chip before?

    My current plan is to pick up ChipQuick and use that.
     

  2. Jh4db536

    Jh4db536 Friend

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    I could pull it for you using hot air if you like. Do you have a replacement ic?
     
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  3. Luckbad

    Luckbad Basshead - Friend

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    Oh nice! I don't yet, but I can order 4 chips and have them ready.
     
  4. sfoclt

    sfoclt Friend

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    I'm a well-known provider of hot air should you need any.
     
  5. Luckbad

    Luckbad Basshead - Friend

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    I ordered some of that Chip Quik SMD1 and will try it on one of the blown DAC chips. If I can't get it figured out, I'll take you up on the hot air offer.
     
  6. Clemmaster

    Clemmaster Friend

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    Cut the pins and take out the chip first. Then you can unsolder the pins one by one.

    I replaced a PCM63 in my Theta GenV.
     
  7. peef

    peef Acquaintance

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    Where did you source your PCM63? I blew one and am not sure I want to play eBay roulette.
     
  8. Clemmaster

    Clemmaster Friend

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    I played the eBay roulette...
     
  9. dBel84

    dBel84 Friend

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    Using a hot air station makes the job very simple, also limits any chance of damaging the board.

    Happy to help if other offers fall through for whatever reason.

    ..dB
     
  10. Luckbad

    Luckbad Basshead - Friend

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    Chip Quik worked surprisingly well.
     
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  11. dBel84

    dBel84 Friend

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    Good to know.
     
  12. Luckbad

    Luckbad Basshead - Friend

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    So Chip Quik worked well to remove the chips, but I had trouble removing 100% of the solder afterward, and soldering smaller PCM1704 chips into place when there are other components still there proved more difficult than I'm apparently capable of.

    @dBel84 or @Jh4db536 I might take you up on the help if you're still willing to help out and I don't find someone at work who knows what they're doing.
     
  13. elguapo

    elguapo Acquaintance

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    Just curious, does anyone here know what a blown DAC chip sounds like? I have an old Bel Canto DAC that has gone bad. I don't really have the time to troubleshoot it, but if it's as simple as swapping out a chip then that should be pretty easy.
     
  14. Jh4db536

    Jh4db536 Friend

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    Sure, are you going to the meet on Saturday? Is it just solder stuck in the PCB holes that need to be sucked out? smd pin pads need wick?

    Let me know. I'm more available in mid August.
     
    Last edited: Jul 11, 2017
  15. Luckbad

    Luckbad Basshead - Friend

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    Can't make anything Saturday. Got a work thing to go to.

    It's SMD pin pads that need wick and I need to actually mount the PCM1704 chips properly. I tried doing it by hand with a chisel tip but failed miserably. Partly because I've never done something at that scale, but partly because there are capacitors all around the same area and I had to come in at a bad angle to even attempt it.
     
  16. Mr.Sneis

    Mr.Sneis Friend

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    Heh, I technically have about 4 1704 chips but PCX has my dac hostage still :( Not looking great.

    SMD is ballsy work, the pads need to stay put obviously, with my luck I'd have tried the solder wick and overheated the pads. I know a few guys locally that have offered to do hot air rework though.
     
  17. Clemmaster

    Clemmaster Friend

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    Do you use rosin flux? Makes soldering MUCH easier.

    You need to solder one of the external pin, first, to hold it tight. Then work your way, pin by pin, from the opposite side.
    Allow few seconds between each pin, to let the packaging cool down a bit.
     

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