Desoldering help

Discussion in 'General Electronics Chat' started by Aussie dave, Feb 19, 2015.

  1. Aussie dave

    Thread Starter New Member

    Feb 19, 2015
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    hey
    I just joined this forum so hopefully I post in the right area, looks like a great place to learn, ok I just started soldering so still trying to work things out, can anyone tell me if the charger ports and all other components are originally lead free or lead on laptop boards? I've got a practice motherboard to play with but man trying to get the solder out of the joints of the port is failing miserably, I'm using a solder wick to try extract it but it's not really taking much, I've tried putting lead solder in to try loosen it, tried using different heat at 600-700F I got one or 2 pins lose but the ones directly under the port aren't working, and I can only get to them on the secondary side of the board, is there something I'm doing wrong?? Any tips? I'm using a pace 250 mbt rework station, thanks heaps in advance
     
  2. #12

    Expert

    Nov 30, 2010
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    This is why solder suckers were invented. Do you have one?
     
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  3. Kermit2

    AAC Fanatic!

    Feb 5, 2010
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    try using a heat gun or blow dryer to pre heat any parts the have a lot of metal. most small irons cannot supply enough heat on their own.
     
  4. Aussie dave

    Thread Starter New Member

    Feb 19, 2015
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    I got a desoldering gun that came with my station but once the solder from the top is sucked up, it doesn't like to get the solder down in the hole like it's not getting enough heat down there, never tried a blow dryer but shall try that
     
  5. MrChips

    Moderator

    Oct 2, 2009
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    Complex PCB like computer MB are multi-layer boards. They usually have a POWER plane and a GND plane on inner layers which you cannot see. They suck the heat away from a soldering iron.

    It is very difficult to unsolder multi-lead components since you have to get all the pins unsoldered.

    For single solder joints I use two solder irons, one on each side of the board.

    You need a heat gun that gets up to 800°F.
     
    Last edited: Feb 20, 2015
    planeguy67 and #12 like this.
  6. Aussie dave

    Thread Starter New Member

    Feb 19, 2015
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    My gun goes that high, so try 800 with the wick and I'll have better luck?
     
  7. MrChips

    Moderator

    Oct 2, 2009
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    I have next to zero experience in PCB rework. If you have a heat gun I would attempt to heat all the solder pads of the component and then try to wiggle it off the board using moderate force.
     
  8. #12

    Expert

    Nov 30, 2010
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    You already know my opinion: Heat it up and use the solder sucker.
    No point in typing this. You would have tried that anyway.

    I have worked in such a factory and the secret to immaculate repairs was a clean hole.
    Then again, if you can wiggle the part out, sucking the hole clean is even easier.

    If you are replacing a dead part, you might cut the legs off and remove one at a time.
     
  9. MrChips

    Moderator

    Oct 2, 2009
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    Most simple components have signal pins and one each of power and ground pin.
    You can try using a solder sucker to free the signal pins.
    Then wiggle the component off by going back and forth on the power and ground pin.

    If you have multiple power and ground pins, you have to use the heat gun and get them all at the same time.
     
  10. ian field

    Distinguished Member

    Oct 27, 2012
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    If you're trying to salvage a connector from a scrap board to replace one on a board for repair - I'd proceed as follows: Remove the salvage part from the scrap board with a modeller's pencil blowtorch - it gets all the solder joints up to temperature together and quickly to minimise risk of damage.

    Usually the easiest way to remove a connector from the board you're repairing - is to destroy the connector so you can unsolder its pins one by one.

    Different connectors need different approaches - if you can get at the pins to snip them, its dead easy.

    Its probably safe to assume original manufacture was with lead free solder - 60/40 melts at a lower temperature, so it can make life easier when handling lots of pins.
     
  11. Aussie dave

    Thread Starter New Member

    Feb 19, 2015
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    Thanks for all the advice, I ended up cutting up the old port so I could see the port pins and then used my desoldering gun to suck it out and wick to help clean up and raised the heat to 800F, i work in an IT repair shop so i got myself a bad board and practiced on that before I attempt customers stuff, thanks for the advice muchly appreciated, just gotta work on being a little cleaner when desoldering and I'll be right
     
  12. ian field

    Distinguished Member

    Oct 27, 2012
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    Personally, I gave up on wick - it just doesn't work for me.

    I prefer the spring loaded piston type solder sucker, some people advise against those because they have slight recoil, and can knock pads off if you're not careful. IME; clearing through plated holes without one is very difficult.

    You can get desoldering irons with a hollow tip and a steel tube with a rubber bulb on the end for sucking away the solder - or if you've got deep pockets, the deluxe version has an electric pump.

    Successful desoldering usually requires additional flux - this usually ends up as carbonised deposits in a hollow desoldering tip, keeping the hole clear without damaging the plating is a knack that takes time to learn!
     
  13. Aussie dave

    Thread Starter New Member

    Feb 19, 2015
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    Yeh does take some practice, been doing quiet a bit of practice on broken boards, I don't find wick all that effective, helps in little things here and there. Another question, my work station has a tip offset function, been researching to try and find out what this does, can anyone help explain it??
     
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