The following causes have been found to cause problems with the SIGM20:
- Is the LocoNet cable plugged into front of UP3 or similar utility panel? The front connectors are suitable only for throttles because the rail_sync signals (a version of the DCC track signal) is not passed out to the front connectors. The LocoNet cable must always be connected to the rear connectors.
- Are the LocoNet cables OK? We are aware of several instances where a LocoNet cable that passes a test with an LT1 tester is actually high resistance, affecting the messaging.
- Is the jumper JP1 on the board removed? These should be REMOVED for normal operation, and only inserted for programming on a programming track.
- Is the board's green LED lit? If not, this suggests a problem with LocoNet cabling, or the track power is currently switched off.