On Thu, 18 Dec 2003 11:42:58 -0500 Kalman Rubinson
wrote:

Weller sells, through distributors, replacement parts. I suggest that
you replace the temp-sensing tip element, as a start.

The only heat sensing element in the WTCP? series is the lump of metal
at the tail end of the tip. The correct tips for this iron will have a
separate bit there with a single digit stamped in it. That's normally
a 7, for 700 degrees F.

The alloy of this lump is chosen to have a Curie temp of 700F and it
will never change.

There is a magnet that runs down toward the tip and is attracted to
the tip when the tip is below its Curie point. Once the temp reaches
the Curie temp the lump no longer attracts the magnet and the magnet
is pulled back upwards by a small spring. This opens a switch in the
handle and turns off the heating element.

The usual problems with these are that something gets inside the
sleeve behind the tip and jams the magnet so it can no longer move, or
the switch contacts weld closed.

With the iron off and cold you can remove the tip retaining sleeve.
When you pull the tip out you should feel the pull of the magnet and
then feel the switch and magnet snap back into the barrel once the tip
is too far away to attract the magnet. You should repeat this to
verify that the magnet is free to move.

If you unplug the iron from the base and put an Ohmmeter on the pins
of the iron, you should see the continuity come and go as you take the
pin in and out.

Weller is owned by Cooper Tools and PDF files of replacement parts are
available on their web site.

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Jim Adney
Madison, WI 53711 USA
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