David C. Partridge said:
Hot air paint stripping gun - not ideal as the air flow rate is rather
high (risk of blowing parts off the board as the solder melts) and too
large an area heated typically, but if push comes to shove it will do the
job.
Dave
They usually come out easily enough, if you heat what tiny piece of the leg
is visible, one side at a time, and add new solder. Use a reasonable power
iron eg 30-40 watts, and fitted with a pointed tip. The existing solder
will then melt right under the leg, and you can lift up the first side
simply by leaning the body of the cap over a few degrees. Then go back to
the other side, and reheat its leg. This one will usually then allow the cap
to lean over far enough the opposite way, to get that leg right off the
board. Back to the other side, and one more application of the iron, will
fetch that leg off also. Clean up the pads with desolder braid. Make sure
you noted carefully which was the " + " side of the cap, before fitting a
new one. Place new one on pads, and hold on with your index finger tip.
Apply iron to one side, and hold it there for a couple of seconds. The
tinning on the pad and leg, will hold the cap 'tacked' in place. Now heat
the other side, and apply a tiny amount of fine gauge solder. Finally,
reheat the first side, again applying solder.
Whilst using a heat gun is ok if you're experienced, I would caution against
it, if you're not, and don't want to see a neat pile of other surface
mounted components that were nearby the one you wanted off, all sitting on
your bench ...
Cutting the cap is also a workable method, but be careful if you do, that
you don't sqash the bottom of the cap too, and tear the legs, complete with
pads, off the board. I would agree with Anton above, who said in his post
that good soldering equipment is an investment, but I also completely
understand that this is often not a practical proposition for the
non-professional, who'd only going to use it once a year.
Arfa
