"alpha_uma" wrote in message
news:UChQc.13636$gE.8616@pd7tw3no...
Hi, all. Need some tips on soldering and unsoldering MOSFETs.

On unsoldering (bad) ones: They are of the types with fins soldered on to
the surface of the board. Do I just apply heat to the top of the fin (D),
and then lift the MOSFET to an upright position before unsoldering its two
outer legs (G & S)?

If you have no intention of reusing them, cut the leads first (close to the
device). Grab the device with pliers and apply heat. Then, remove the
leads one at a time.

On soldering good ones: Are there any heat precaution when soldering a new
MOSFET? Should I clamp the top of MOSFET to a heat sink before applying
heat
to its legs? Would a 40W iron be too hot for the job for an amateur hand?

40 W is about right for the device itself and is OK for the leads if you
work quickly. However, you might get delamination of the foil on some
circuit boards.