You didn't say whether you looked inside the Pace tweezer plug, but if
you're going to relocate the heater wires you'll probably end up doing
I was gonna modify the socket. I have other places to plug the iron.
I'm quite confident that you will find only 3 wires going to the
handpiece, as mentioned before.
Well...hate to shatter your confidence.
The info is here: www.paceworldwide.com/sites/default/files/TT-65.pdf
it includes a schematic showing the sensor.
Here's the troubleshooting chart for the PACE TT-65 handpiece:
Was a PDF chart that got copied as text, but you can see the
SYMPTOM CHECKOUT PROCEDURE CAUSE SOLUTION
Check resistance - Pin 2 to
Pin 5. Resistance should
be 10 ohms.
If not - -Open Heater
______________Here's the relevant part
Check resistance - Pin 3 to
Pin 6. Resistance should
be 110 ohms.
reads less than 105 ohms - -Shorted Sensor
____________End of relevant part.
If you stick the hot tip of any of the irons I was speaking of earlier
onto a cold surface, the LED will change from briefly coming on
(idling), to come on steady.. and yet, there are NO sensor leads going
to the handpiece (only because there is NO SENSOR).
The same LED action is seen when the adjustable temp control is turned
up/increased from a previously lower operating temp.. when the higher
temp is reached, the LED returns to briefly coming on (idling again).
I believe that you have experience that leads you to a conclusion
that is incorrect for the systems I have.
Your conclusion seems to be contrary to all my experience. I fail
to understand how power input can change with heat load
without sensing something.
I know of three ways in use to have temperature control with two
active wires (plus safety/static ground).
I have used irons using all three methods.
1)put ALL the electronic controls in the handpiece.
2)the weller magnastat that uses a thermally activated switch in the
3)the Metcal system that pumps RF down the cable and uses a property
of material in the head to absorb the RF and heat only when below
the transition temperature of the tip.
This article describes various systems.
I obviously don't need to say this, but.. hey, don't take my word for
I won't, because I haven't heard a rational explanation.
Can you describe the mechanism that allows
the power input to change based on heat flow without sensing
Finding a calibration pot in the plug doesn't demonstrate that a sensor
does not exist.
Buy a used Ungar soldering iron handpiece with the same 6-pin
connector on eBag and open the connector.
It doesn't even need to be a working iron.. doesn't even need a heater,
so it should be possible to find one cheap.
I'm sure I have several extra handpieces, but don't know where to look
You don't need an extra one. Just unplug one and take a meter to it.
The sensor in my Weller EC1301 sensor measures 27 ohms cold and about
43 ohms at 700F.
The only adjustable power supply that I own with the UNGAR name
is the aforementioned 9900AS. It has WAY MORE circuitry than
would be required for open-loop power control (light dimmer style).
The number and type of integrated circuits is consistent with
the schematics for the PACE temperature control systems.
Not having a handpiece or schematic, I can't prove it. I can only
that the power out is dependent on the value of a resistor plugged
into the socket...assumed to be the sensor. It appears that the
type of sensor varies much more with temperature (in the 5K to 10K
region) than the sensor
used by the PACE or Weller EC series.
Are we having fun yet?