"KCS" v3.9.1 firmware BIN file download

[twostar]

I think I've found the problem, it's caused by the way the output circuitry is set up.  The output LED for e.g. DO1 is lit when there's a voltage between Y1 and GND, whether the output is on or not.  In other words instead of being before the output MOSFET, which would only cause it to be lit when the TLP181 optocoupler output is on, it's after the MOSFET, so if Y1 is connected to something with a pullup then the output LED will be lit even with the MOSFET switched off.

I'll need to do some rewiring tomorrow to test this, I'll post the results here.