Redhatcc Posted July 8, 2009 Share Posted July 8, 2009 I was replacing some caps on a dell motherboard, and some of the soilders just will not melt so i can remove the caps... i tried different points on the soilder gun, i tried putting down soilder then removing it with copper wire. Any tips on removing capacitors from motherboards when you just can not seem to get the soilder on the bad caps to melt so you can remove the bad caps? Any help is appreciated Link to comment Share on other sites More sharing options...
CoffeeFiend Posted July 8, 2009 Share Posted July 8, 2009 Often that's because the caps' leads are soldered not only on the top and bottom layers, but also into an internal ground plane and the like (sometimes several). Quality boards with thicker copper makes it worse, same for designs that don't use thermal reliefs. You try to heat it up, but the nice layers of copper (which conducts heat quite well) of the PCB dissipates it. And heating it brutally will likely result in lifted pads (especially if you're not too experienced at this, n00bs often manage to lift whole tracks). Doing work on fancy PCBs like motherboards (tiny traces, lots of layers) isn't for beginners. This is where having the proper tools and experience helps. (braid/wick won't do you any good here). Mind you the boards affected by the problem (usually mid-era P4 boards) aren't even worth the time wasted doing it (look at the price of a new board, minus the price of suitable replacement parts with shipping/handling/taxes and all, divided by the time desoldering/soldering/looking for parts and all that, and you'll find it pays very, very little) Link to comment Share on other sites More sharing options...
Redhatcc Posted July 8, 2009 Author Share Posted July 8, 2009 that does make alot of since. i did take the caps from another board and they were removed quite easily, but this board is alot harder to remove the caps from and like you said above ^the soilder gun that i have operates around 900 degrees F and works really well with everything else i have done with it, just was a bit puzzled today when this happened. just was weird that the soilder on the bottom did not seem to melt any at all, but like you said a well built board the copper would probably spread the heat pretty rapidly and nice so :/ Link to comment Share on other sites More sharing options...
leon Posted July 8, 2009 Share Posted July 8, 2009 This can be because now they use leadfree solder and it melts at higher temperature then usual solder.I had some problems with this new solder too. Link to comment Share on other sites More sharing options...
Redhatcc Posted July 9, 2009 Author Share Posted July 9, 2009 I was thinking something had to be different. Its not as much as the soilder will not melt all the way through, but even when i place the soilder gun on top of the soilder nothing what so ever even begins to melt. Link to comment Share on other sites More sharing options...
Ponch Posted July 9, 2009 Share Posted July 9, 2009 If you can pull them from one side while you melt the metal without burning yourself, that's how I've done it. They're bad caps anyway. Having a vacuum pump helped as well. Link to comment Share on other sites More sharing options...
puntoMX Posted July 9, 2009 Share Posted July 9, 2009 Forget to change the caps on that one, it's impossible to do that on that board. You need a lot of heat to get the whole ground plate hot enough to rip the capasitors off. You will melt other components and layers before it even gets hot enough .Been there New mobo, new case... and welcome to dell... Link to comment Share on other sites More sharing options...
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