Solder gets into capacitor lead holes

[Northeastern292]

Guys,

I have an issue when me and my stepdad are replacing caps on an iMac G5 1.8GHz 20'' model. The issue that comes up is that solder gets into the capacitor lead holes, and what happens is that I can't put the new caps in.

Would a simple desoldering pump (a la vacuum pump) do the trick, or am I back to heating up needles?

I do hope that this isn't a stupid question at all.

[Toasty]

Re: Solder gets into capacitor lead holes

Reflow the hole with fresh solder then use solder-wick and a needle. You don't have to heat the needles. A solder pump will work, but you still need to reflow them. Have a setup to hold the board firmly while you heat one side and use the pump on the other.

You may still need to revert to a needle. Just the way these boards are.

Toast

[Dgtech]

Re: Solder gets into capacitor lead holes

Everyone that solders at some point runs into this situation.
There are different ways to clear the hole:
1. Sometimes using a dental pick will work.
2. Sometimes adding solder to the hole and then removing it will work.
3. Solder wick works also.
4. Sometimes adding a touch of liquit flux to the hole (just a touch) will make the solder wick around to the side copper in which clears the hole.

[Northeastern292]

Re: Solder gets into capacitor lead holes

Thanks! I'll have to try some of those tips.

[severach]

Re: Solder gets into capacitor lead holes

Needles aren't strong enough and can't be sized exactly and may be too small to pass the leads. The sharp point doesn't help. I had to do an entire G5 and I hit upon an excellent solution: a drill bit, but not the sharp end. The drill can be sized exactly and will clear the hole quickly and completely, will not bend or be damaged from the heat, and will not damage the through hole plating. Solder will not stick to a drill bit.

After the caps have been removed with the standard rocking technique, chuck the right size drill bit into a small needle nose vice-grip with the dull end extending out a bit more than the thickness of the board. Heat and press until the drill pops through. A desoldering gun with a hole in the center is best but a standard iron will work. Most of the solder is pushed into the desoldering gun without suction so the gun has plenty of solder on the tip to heat the next hole. Removing the rest isn't necessary.

Hold the board with any padded adjustable bar clamp like Harbor Freight 46808 or Craftsman 00931485000. A 18" bar is heavy enough to hold a motherboard. Some boards may require two clamps or larger pads.

Each hole takes about 15 seconds to clear, faster if there is residual heat. A full recap on a G5 board should take no more than 45 minutes.

[PCBONEZ]

Re: Solder gets into capacitor lead holes

I used a properly sized stainless steel needle [easy to find anywhere that sells sewing supplies] chucked into an ALL METAL exacto knife handle.

Works perfectly well.
Easy to use too because the solder doesn't bond to stainless.

.

.

[willawake]

Re: Solder gets into capacitor lead holes

needles - you wiggle them