Looking for tips to desolder surface mount IC's

Discussion in 'General Electronics Chat' started by RodneyB, Oct 31, 2014.

  1. RodneyB

    Thread Starter Active Member

    Apr 28, 2012
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    I am trying to remove some what I assume are 80 pin IC's from a double side PCB. I don't have a hot air station and looking for some tips on how to do this without damaging the board or the components around the IC
     
  2. GopherT

    AAC Fanatic!

    Nov 23, 2012
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    Easiest way is to get a cheap hot air gun (workshop version of a hair dryer). Grab the part with a pair of pliers and lift gently until part of the board is off the workbench. Then apply heat until the board falls to the bench and the part is in your pliers.
     
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  3. ISB123

    Well-Known Member

    May 21, 2014
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    You can use 0.5mm wire to remove smd IC's but only ones that don't have thermal pads.
    1.Take a wire and place it behind the pins.
    2.Using soldering iron apply heat to the pins.
    3.Pull the wire while the soldering iron is on the pin/pins.That should lift the IC's pin and prevent the IC to be soldered again.
    4.Repeat until you de-solder all the pins.
    [​IMG]
     
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  4. Kermit2

    AAC Fanatic!

    Feb 5, 2010
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    ive used the same technique, but used a .003 in feeler gage to slide under each pin as i went down the row with an iron. you have to leech up as much solder as you can with solder wick first.
     
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  5. RodneyB

    Thread Starter Active Member

    Apr 28, 2012
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    Will this effect the other components near to the IC
     
  6. ISB123

    Well-Known Member

    May 21, 2014
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    Depends on the size of hot air gun's nozzle.
    When you buy one you should get few nozzles in different sizes.
     
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  7. RodneyB

    Thread Starter Active Member

    Apr 28, 2012
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    These are the two IC's I am trying to remove
     
  8. ISB123

    Well-Known Member

    May 21, 2014
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    What kind of package are they in and what is their name?
    And do you need those IC's or they are damaged?
     
  9. RodneyB

    Thread Starter Active Member

    Apr 28, 2012
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    Attached Pictures
     
  10. RodneyB

    Thread Starter Active Member

    Apr 28, 2012
    633
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    Attached 2
     
  11. ISB123

    Well-Known Member

    May 21, 2014
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    Wire technique could work on those,they don't have thermal pads.
     
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  12. RodneyB

    Thread Starter Active Member

    Apr 28, 2012
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    The IC's are damaged. I want to be able to remove them and then replace them with new ones
     
  13. RodneyB

    Thread Starter Active Member

    Apr 28, 2012
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    I will try take photos and then post my success or failure with details
     
  14. ISB123

    Well-Known Member

    May 21, 2014
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    Since they are damaged you could just slide a small screwdriver under them and gently lift while de-soldering.But if there are any traces under the IC's dont do it with screwdriver then.
     
  15. ian field

    Distinguished Member

    Oct 27, 2012
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    Its unusual to want to save *BOTH* the chip *AND* the board - the usual scenario is wanting to remove a dud chip from one board and salvage its replacement from another.

    The easiest way to shift the dud chip, is to shear all the pins flush with the header. A sturdy craft knife is handy for this as long as you take care not to cut into any tracks underneath.

    The donor PCB won't be much use without the chip you're taking off it - I heat the other side with a modeller's pencil blowtorch, some people just place the board on a hot plate.

    If you're that desperate to shift the dud chip without damaging it, you could use a hot air gun as others have suggested - but a hot air gun can easily scorch the PCB if you're not careful.

    I've scorched a few boards that way, and once or twice I got away with blowtorching without any scorching - a lot depends on the quality of the PCB material.
     
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  16. Stuntman

    Active Member

    Mar 28, 2011
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    If you want to be careful with other parts on the board (especially those plastic housings for the ethernet ports), go grab some aluminum foil, and cut a hole roughly larger than the size of the component you want to remove. Press the aluminum foil down on the board in a manner that very heat sensitive components (like the plastic housings) do not touch the foil directly, and adjacent components are simply covered while the part to be removed remains visible. This generally gives plenty of shielding to the rest of the components.

    The best tool for getting these (and other high density SMD chips) off the board is this:
    [​IMG]
    You slide this under the chip body or leads (similar to how someone else mentioned with wire), put some tension on the chip, then heat evenly with your gun. When the IC is ready, the IC will pop out of place (and sometimes across the room).

    Many of these types of components are put on with lead free solder, which makes the process a little more difficult as the solder takes more heat to melt.
     
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  17. ErnieM

    AAC Fanatic!

    Apr 24, 2011
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    With just a pencil type iron I would try to salvage the IC like so:

    Start with some solder wick to remove as much solder as possible from one side or the other, then with any suitable tool such as an (Exacto blade) pry up each pin in turn till one side is loose.

    You may try the same approach on the other side or... you may be able to flow the other side (blob on lots of solder) till it lifts up. Work each side till you can lift it off.

    Work slow and let the chip cool off between attempts.

    That said, hot air is still the best way to remove this.
     
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  18. Dr.killjoy

    Well-Known Member

    Apr 28, 2013
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    I use Chipquik for stuff like this .... Also cut the leads off and desolder the broken pins ... I have seen people use thick copper wire and shape it around the chip with tin on the surfaces that meet the chip and iron...[​IMG]
     
    Last edited: Nov 1, 2014
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  19. ian field

    Distinguished Member

    Oct 27, 2012
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    Only just remembered - I've seen advertised; a very low melting point solder that you alloy into the solder already there, it lowers that solder melting point and makes removal much easier.
     
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  20. ISB123

    Well-Known Member

    May 21, 2014
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    Seems like it would need 50W soldering iron.
     
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