I haven't had a 9900 series controller, but I do have a few 4000 series
desoldering stations, and there should be 3 conductors from the plug.

By taking the cover off the unit, you should be able to determine which
connector pin is for earth ground (the heater barrel & tip), and the 2 pins
for the heater.
I'm fairly certain that there are not any other pins used (no temp feedback
device).. I've only seen 3 conductors used for Ungar handpieces/irons.

--
Cheers,
WB
..............


"mike" wrote in message
...
I have a Pace tweezer soldering iron. 21V
I have an Ungar 9900AS power unit. 24V
I'd like to mate them.
The 6-pin round connector plugs in...I'm afraid to turn it on.
I found some pinout info on Pace systems,
but nothing on the Ungar.

A schematic or pinout info would save me reverse engineering the
thing.

Thanks, mike