JBC soldering station - automatic fan hack

[leo938]

Hello all,

I have a JBC station, similar to the one Dave reviewed in episode #472 (https://lbry.tv/@eevblog:7/eevblog-472-jbc-cd-2bb-soldering-iron:8)

I'd like to alter/hack the station so that once the iron is removed from the station it activates a smoke removal fan & switches it off (after a short delay) once the iron is replaced.

After examining the unit I discovered that the outer ring on the soldering iron is connected to one of the pins (number 5 I think) in the soldering iron connector. Using this connector & the metal receptor which it contacts on the soldering station it should be relatively straightforward (I think) to trigger something like an opto-coupler that would trigger the fan appropriately.

However the only issue might be is that the soldering station also uses this connection to signal (via the dsPIC) the heating of the iron (see video at  2:45 & 9:13).

From my understanding once the signal is a few volts & separate from the soldering station supply it should be relatively safe, but before I destroy a very good station I'd appreciate any thoughts from others.

Thanks for reading,

Leo

[Hydron]

On my JBC station (the BT-2BWA model) the iron stand has a 5V pullup (i think on the order of 10k) which is grounded by the iron to signal that it is in the holder. Should be pretty easy to add an isolated output to the station using this signal, the internal power rail of the station, a mosfet, an opto-coupler and a resistor - is something you could hack up on bit of verroboard and just chuck inside.

There is also another thread floating around with a full JBC schematic that the poster has reverse engineered - may be of use.

[leo938]

Many thanks for the idea, will take a look

[leo938]

Here's the link to the full breakdown of the schematic of the iron:

https://www.eevblog.com/forum/testgear/jbc-soldering-station-cd-2bc-complete-schematic-analysis/

Using this I discovered a usable solution. From the picture below the signal from the stand to the top of the zener (marked SIG in the picture) is grounded when the iron is in the stand & approx a 100Hz square wave when out. Please note that this is in reference to the GND marked in the picture, not the ESD ground at the back of the iron. Using this a tap from the 3.3v regulator it should be straightforward to implement an optocoupler solution.