On Thu, 18 Dec 2003 18:08:22 GMT, "Michael A. Terrell"
wrote:

Joshua G Senecal wrote:

Hi all,

I have a Weller WTCPS soldering station with a 201U power supply and 201P
iron, using a 700 degree F tip. Last night I powered it up in preparation
for soldering some connectors, and a few minutes later I saw that the tip
and metal shaft of the iron were glowing red-hot.


A bad thermostat is a likely cause.

Agreed, had it happen myself. Not sure about the specific model but
ISTR the thermostat is in, and indivisible from, the element.

The "bit" has a lump of Iron with certain temperature chararistics (
peltier effect ? ). When the temperature exceeds the Iron magnetic
ability the element switch, ( with a magnet on the actuating arm ),
drops out until the Iron, ( this is the Iron on the bit ), regains its
magnetic ability.
KISS in its best form. I have managed to "unstick" the magnet before
now, but its a bugger to do.
Sorry I can't describe the operation in a more scientific language,
but I'm sure someone will ba able to... ;-)

hth Mike W, G8NXD