Updated schematic in first post as I made a small mistake with RN1.

Quote Originally Posted by EddyCurrent View Post
It says AC beside the socket and as Clive says the diode would indicate this is true.
I am sure it's DC going in, my Multimeter showed 0 for AC and 24v for DC. It's also coming from the same PSU that drives the stepper motors, wouldn't that be DC?

Regards,

Les