This is what I know about the Weller five-pin soldering iron system.

As far as I can tell, they all operate at 24V with bang-bang controls.
The EC1002 is one of many power supplies designed to operate with the 
EC1201A handset.

The EC1201P handset is the same thing as the EC1201A just with a nonconductive
plastic handle instead of a conductive plastic.  The TC201T seems to be the
same.

These handsets have two gold-plated pins and three tin-plated ones.  The
gold-plated ones go to the thermal sensor and they should read about 
21-27 ohms between them if the sensor is good.  One of the tin-plated ones
is ground and is connected to the metal case.  The other two are the heating
element and they should have 12-14 ohms between them.

Some time around 1998 they changed the EC1201A from a unit that had a heating
element with leads to a newer design that used pins.  The newer ones with pins
take an EC234 replacement element.  The older ones with leads require a
TC208 replacement element, combined with a BA60 adaptor to deal with the 
flared barrel.  The EC229 temperature sensor will fit both the new and the old
ones.


Scott Dorsey, 2010