Series 4 processor orange LED (RX) meaning on BUS
I have a ~10 year old Homeworks series 4 processor that runs several dimmers. Motion detector for lights on stairs stopped working a few days ago (meaning walking up or down stairs no longer triggers lights to come on). Have traced the wires back to the series 4 processor BUS 3.
BUS 3 on the side where the orange LED is on full-time does not respond to a voltage meter (all other BUS and switches do respond). Can someone tell me what might be the problem?
Everything else on the system seems to be working fine.
I have tried to upload pictures, but the attachment manager keeps telling me the files could not be uploaded/upload failed (?)