Originally Posted by tignmeg
The thermistor wires are connected to pins 9 and 10 of the controller which is the sensor input. If the sensor in the soldering iron was a k-type thermocouple then that is all that would be required. Unfortunately the thermocouples in the HAKKO irons are a themistor so it needs a resistance across pins 8 and 9 so that the controller can correctly sense the temperature. A 10k ohm variable resistor is connected and this resistance needs to be adjusted to calibrate the temperature correctly.
Hi, I am having a bit of trouble with this - I am not sure if I have the same idea in my head as to how this is set up.
So you have the temperature sense pins from the Hakko going to pins 9 and 10 of the controller - but you have a resistor across 8 and 9? I tried this and could not get mine to alter the detected temperature.
I think I need to add around 100k in series with the Hakko temperature sensor to then bring it to the same "range" as the P100 type sensor, and then use this with the PTC100 sensor setting.
Any other hints or tips? I have completely melted one soldering iron as it heated up way too quickly and the controller never saw the massive temperature difference.
I've noticed on mine the controller wants both 8 and 9 tied together and then the PTC100 across 9 and 10 - that's what is in the diagrams I have, so I was wondering how you came across the resistor across 8 and 9 and how this influences the input.