Unsoldering problem

[IcyBurn]

I been trying to unsolder a blown capacitor off the motherboard and it will not melt the solder at all, i try different solder iron and tips and none seem to melt the solder i even add solder on the one im trying to melt for a better contact but still nothen. So if any one can help with problem thanks.

[Salmon Trout]

Lead free solder has melting point from 5 to 20 deg C higher than lead/tin so maybe your soldering irons are not hot enough. Also, is your tip clean, and well coated with clean solder? Have you been taught how to use a soldering iron?

[Karnac]

Some tips here...

http://www.thecapking.com/howto.html

[squall_01]

buy a new board, its tring to tell you something there is a good reason why it had failed.  Its rather hard to replace this stuff unless your real sure what to do.

[Salmon Trout]

The secret is to use a clean, hot, tinned, temperature controlled iron with the right kind of tip and to be very quick. Poking about with a soldering iron when you are unskilled and/or don't know what you are doing is a good way to kill a motherboard. The conducted heat can damage components and cause the multiple layers to become delaminated

[westom]

I been trying to unsolder a blown capacitor off the motherboard and it will not melt the solder at all,

  Simple trick: first apply some regular solder between your iron's tip and that existing solder.  Then all solder will melt easily and be removed with a solder sucker.

[squall_01]

its a good tip dont mean it will work.  You should at least have fresh solder on the tip when your doing projects.

[westom]

its a good tip dont mean it will work. 

  The technique works because it comes from someone who actually does this stuff.  If you did this stuff, you knew that thin layer of solder on the tip is not sufficient.

[alexK]

IcyBurn,

use a de-soldering iron. This a soldering Iron with tube like tip that has a suction bellow attached to it. I have not had much luck with it, but you should try. An other technique is to hold board in a 60 degree angle so that the soldering iron is upside down and below the board, so that the solder can drip down the iron.

I wonder if all that "repair" is useful, de-soldering does a lot of damage. Any part on the board has been installed in a split second, and just the right solder temperature. De-soldering generates excessive heat, and does unrepairable damage to the surroundings, such as carbonizing the board. This will cause current to jump (like in a broken car distributor).

If the capacitor is not puffed up,  loose or physically damaged, what makes you so sure that it blown? Testing the MF of capacitor is difficult, and almost impossible if it still installed in a board!


 

[patio]

You should not be doing this yourself no matter all the advice being given...
Unless you can afford a new MBoard.

[Gizmologist]

As usual Patio is correct. Trying to desolder a questionable component from a very finely traced printed circuit board is not something that should be attempted by anyone with the experience and correct tools. Even those who have both the knowledge and the tools can sometimes end up with a bad situation.

Apply too much heat or for too long and the copper trace can lift off the board. Too large an iron or careless (unintentional) shorting of closely spaced pads by a blob of solder may not be noticed and you end up doing more damage.

Another poster also asked the question as to why you think the cap is blown. This was covered in great detail a few days ago. Keep in mind that electrolytic (polarized) caps blow for cause. In other words there may well be other parts that are damaged that you are not aware of.

Although I do have the professional desoldering station equipment. I have found the most reliable method is to use solder wick. This looks like bare copper braid off a shielded cable but it is impregnated with flux just like the original solder. This makes the solderwick just"wick" up the solder and will draw solder out of holes on the board.

[squall_01]

Patio I already mentioned that as something that he sould just do. holy crap that is so funny.  Cause for once thats were your wrong westom boom....  ah there everyone can feel better.