"I've had great success using my weller WTCP iron with a 35 watt element
and a large chisel tip. and you need lots of solder wick. "
A bigger (higher power) iron means more heat capacity and faster
heating, so less time to destroy things. A 35 watt is fine. I would not
try a 15 watt. Even if it is temperature controlled, the big wide tabs
and PCB copper will sink the heat from the iron and drop the temperature
below the set value of the iron. But you do not want a higher
temperature, which will burn things up, like the PCB material, or
separate the copper from the fiberglass. What you want is a chisel tip
(sometimes called screwdriver tip) as wide as the collector tab on the
transistor, on a temperature controlled soldering iron. It does not need
to be an adjustable temperature iron, but it should be a temperature
controlled iron. The difference is that with a temperature controlled
iron, you select a tip (I'm thinking of Weller WTCP and similar irons)
that gives you a fixed temperature. With an adjustable one you have a
knob (or up/down buttons) and a readout that lets you set it. In either
case you want about 700 to 750 Fahrenheit. If you use too low a
temperature you mess around too long and damage things. If you use too
high a temperature you burn stuff up.
You want to get in, melt the solder, and wick it away quickly, and get
out before you cause a lot of damage.
I suggest you find some scrap piece of equipment that has large pieces
of copper (similarly sized as the power transistor tabs) soldered to the
PCB and practice a bit unsoldering and resoldering on the expendable
piece of scrap, before you get into your PA.
DE N6KB
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