Many reported problems turn out to be electrical problems with problems being caused by inadvertent wiring errors.

One issue that has caused problems on several layouts has been incompletely crimped connectors on LocoNet cables. In several instances this has resulted in a connection that has high resistance, but isn't open circuit. The result is that the cable tests OK with an LT1 but doesn't work properly in practice.

This can be tested for by using a multimeter to look at the voltages on the cable. On a "healthy" LocoNet, the voltage measures from DCS100 "ground" terminal to the centre two LocoNet pins should be 10v or more. However if a cable has a high resistance connector, then the voltage down that segment of LocoNet can be dragged down. Voltages as low as 4v have been seen due to this. If you suspect your LocoNet is not working correctly, check the voltages to the centre two pins and investigate if is less that approx. 9-10v.

The outer pair of wires provide "rail sync" signals with the same packets as are present on the rails. These can sometimes become open circuit, often without affecting many devices they're connected to.