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I want to replace swollen capacitors on a motherboard. Unfortunately, when removing one of them, a fragment of a pin has stuck in the PCB:

I tried to remove it using pliers, but it only made the situation worse.

EDIT: I’m more interested in methods that can be achieved using tools available in home.

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    \$\begingroup\$ Did you try to heat the solder joint and then poke the fragment out with a piece of wire (e.g. component lead)? This may be a little bit tricky if the solder joint is connected to a large copper plane with a lot of heat capacity. \$\endgroup\$ – 0x6d64 Jan 19 '12 at 12:07
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    \$\begingroup\$ If a solder sucker won't do the work, I'd try heating the fragment with a soldering iron from one side of the board and, at the same time, pushing the fragment with a needle from the other side of the board \$\endgroup\$ – m.Alin Jan 19 '12 at 13:15
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A large amount of copper is probably acting like a large heat-sink to the pin.
Getting enough heat into board to make joint properly molten all the way through is needed. While also minimising board overheating.

Resolder with new solder so there is a reasonable amount of solder present. More rather than less can help.

  1. Use a solder sucker. Heat solder until well molten and then apply sucker. Apply rapidly after iron tip is removed to ensure solder is as hot as possible. If you have somebody to help of if you have 3 or 4 arms try having sucker held ready by one person while the other heats the contact. Person A does a classic 3 2 1 go! and person applies sucker and sucks. Avoid blocking hole with iron while sucking. More vertical than this in this case.

    Solder sucker in action

    Professional desolderers that heat and then apply vacuum and vibration are also available. Thy work superbly compared to most other means. Finding someone local with one of these would save much playing and possible damage. Here is a cheap one:

    Decent low price desolderer

  2. Similar with solder braid. Lots of new solder will help the whole lot suck out by capillary action. If you have not used solder braid before try it out somwhere else first. There is a certain knack to using it well.

  3. Impact. This can work very well.have board held in such a way that it can be swung against a flat surface so that there is significant impact shock. Heat till molten - Impact shock - check/repeat. Bang board so as to maximise shock but present unintended stress at impact due to eg large force onto a small area. Don't hit so hard as to risk damaging the board.

    Done properly this method is very good. Make that "extremely good". I have used it often over decades.The trick is to not beat the board to death but to give it a firm "slap". Banging a whole motherboard on a flat surface achieves this easily enough. Solder is high density and is expelled quite well by impact, tending to carry lead ends with it. Adequate heating is needed in this and all other cases.

    Method:

    you probably won't find this method in most textbooks :-).

    • Find surface on which you can hit MB on the flat under surface so that it stops abruptly. Table top etc.

    • Work out how you can hold MB so that it can be swung easily to impart "slap".

    • Holding in an electrostatically safe manner is a very major bonus - well touching some grounded parts is probably enough. You wearing a grounding strap is extra points.

    • A thick layer of newspaper would help protect table top and motherboard.

    • Work out how hard you are happy to slap your MB on table top.

    • Heat solder till molten.
      Slap.
      Repeat as required.

  4. Insert small drill down hole while heating. This can work well. Determine what size drill will go though hole comfortably. Probably 0.6mm to 0.8mm OK. maybe not. Small drills get hard to find and expensive. Do not use a drill so large that it damages PTH barrel in through-holes. Hold in micro chuck such as eg older Dremels have.
    Heat joint and push and twist with drill (by hand) as required. Lead may push out easily or fight. Turning drill in hot solder will remove solder or lead progressively. Power drilling also works but should not be needed and is risking more damage

  5. Low temperature fractureable solder. Solder especially made for mechanical removal is available. This is usually used for IC renoval but may well work well enough here. Erode solder with dental pick or similar. One brand is Chip Quick.

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  • \$\begingroup\$ (3) probably isn’t such a good idea — I’m going to use the mobo later… \$\endgroup\$ – kinokijuf Jan 19 '12 at 12:53
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    \$\begingroup\$ @kinokijuf - Done properly (3) is very good. Make that "extremely good". I have used it often over decades.The trick is to not beat it to death but to give it a firm "slap". Banging a whole mobo on a flat surface achieves this easily enough. Solder is high density and is expelled quite well by impact, tending to carry lead ends with it. Adequate heating is needed in this and all cases. \$\endgroup\$ – Russell McMahon Jan 19 '12 at 13:04
  • \$\begingroup\$ Could you please provide pictures for (3)? I have trouble understanding in what order I should do the steps. \$\endgroup\$ – kinokijuf Jan 19 '12 at 14:14
  • \$\begingroup\$ @kinokijuf - You'd need a video - it's "dynamic". But, also simple. Find surface on which you can hit MB on the flat under surface so that it stops abruptly. Table top etc. Work out how you can hold MB so that it can be swung easily to impart "slap". Holding in an electrostatically safe manner is a very major bonus - well touching some grounded parts is probably enough. You wearing a grounding strap is extra points. A thick layer of newspaper would help protect table top and motherboard. Work out how hard you are happy to slap your MB on table top. Heat solder till molten. Slap. repeat. \$\endgroup\$ – Russell McMahon Jan 19 '12 at 22:51
  • \$\begingroup\$ Do I need to ground myself. My home has no grounded contacts :( \$\endgroup\$ – kinokijuf Jan 20 '12 at 15:39
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Solder sucker and/or solder wick.

A solder sucker is a small, manually activated vacume device - you heat up the solder and then trigger the device to suck the solder out.

Solder wick is a copper braid that put onto the solder, then heat. It wicks up the molten solder.

Even if there's a pin in the hole, the sucker or the wick will probably take the pin out with the solder.

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I have successfully used another method - a jewelry drill. It has to have a bit the same size as the leg, and you must be careful to get it centered and straight through the hole, but it works wonders when everything else fails. I replaced a dozen bad caps on a motherboard this way and it works great now.

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  • \$\begingroup\$ I did ot need a jewelry drill - the regular 1mm did the job (while slightly enlarging the hole imust admit) \$\endgroup\$ – kellogs Jan 18 '14 at 16:29
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To remove components like this from motherboards is not easy, the biggest problem is lack of sufficient heat to melt the solder all the way through the hole, this is due to copper planes taking the heat away and acting as heatsinks, you need an iron with a much higher temperature than normal so you can remove the solder quickly and effectively without damaging the board.

As previously mentioned a good solder sucker works well provided you can satisfy the conditions above long enough that the solder is still molten all the way through the hole when you release the plunger.

You can get electric irons with suction which work well but are expensive and not viable for the one off or odd repair. The other method that usually works well for stuck pins is wire pins (you can buy tools with different steel pins), just melt the solder and push the pin through, again the solder needs to be molten and stay molten so you can do this.

Not an easy job any way, but the professional electric soldering irons with suction through the bit are easiest, the bits don't remain effective for very long though. Oh, and a tip, if you are doing caps and at least one hole is clear, then use the pin of the new cap to push through, cut the leg that is going through the clear hole shorter so that you can get the first pin through the blocked hole first, once the first pin is in the hole it should push through the hole easily whilst applying the iron to the solder side, you should clamp or have some one hold the board whilst doing this for safety - in case you slip and burn yourself.

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Use your solder iron to melt the solder, you may want to add a little bit new solder or just use some flux to make the melting easier.

Then the trick is to push out the stuck lead with a sharp pencil. Solder won't stick to pencil and if you hold the pencil in the hole for a second after removing the iron, the hole will be open so the new component can easily be inserted.

pencil

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