On 3/25/2013 10:58 AM, Wild_Bill wrote:
If you take the plug apart on the Ungar soldering iron cable (not fun),
you'll see there is a mini variable resistor inside the plug.. no sensor
used for the iron, in case I forgot to mention that.

The variable resistor is used to set/match the iron temp to the chart
supplied with the soldering station (so all the models have some
consistency when set to lowest to highest temp settings).

If you remove the leads to the soldering iron and put the Pace heater(s)
and ground leads in the same place, the Ungar station will provide
adjustable temperature for the Pace tweezers.

This isn't complex.. essentially the same as a light bulb circuit.

Very interesting.

9900 AS Anti-Static Electronic Soldering System
UTCUTC UTC
SERIESSERIES SERIES
SOLDERING SYSTEMS
This premium, ESD-safe, modular system meets the full range of
electronic soldering applications by
means of four 24V-AC quick-connect micro and macro soldering irons.
Electronically controlled, variable temperature.
System meets military specifications: DOD-STD-2000- 1B, WS-6536E and
MIL-S-45734E.
Temperature range 450
o
F to 850
o
F.
Dimensions 3.33"H x 3.80" W x 7.00"D weight 3 lbs.
120V-AC, 6 Hz., 3-wire grounded. UL Listed.
Two year limited warranty on power base.

Temperature variation less than ++ +10 oF
__________________________________________________ ____

I don't have the ungar iron, just the power unit,
but I remain skeptical.

So, they adjust the power, not the temperature...but the dial is
calibrated in temperature and spec'd within 10 F.

What I did was put a variable resistor on the sense pins.
The duty factor of the power source was a strong function
of the external resistor and only minimally affected by the
setting of the temperature slider.
I can imagine that there's a calibration pot that normalizes
the variation in sensor resistance between units.

It's hard to imagine that they have all that circuitry to implement
a light dimmer.

The pace units actually measure temperature, so it stays constant
under varying loads.
Weller EC3001 works the same way. Draws about 27W cold and ~3W at
temperature, pretty much independent of temperature setting.

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


"mike" wrote in message
...

Can't speak for yours, but my Ungar 9900AS uses two wires for the heater,
two for the temperature sensor and a safety ground.
As does the Pace SensaTemp II tweezer.
Problem is that the Pace us 100 ohm sensor.
The Ungar changes duty factor over the range from about
10K to 5K, so completely different sensor technology.

If I could find a schematic for the Ungar, I'd hack it to work
with the Pace. Just not sufficiently motivated to reverse engineer
the whole thing.