Is the green LED on? If not the board isn't getting DCC signals. Try the following:
- Make sure track power is on (you should be able to drive trains)
- Make sure the LocoNet cable isn't plugged into the front of a UP3/5 type panel
- Make sure the board jumper is removed
Connect a LocoNet cable straight to your command station - does that make a difference?
If you are using a Zephyr: you may need a shorting plug in an unused LocoNet socket if you have few other things connected. This is a plug that joins together pins 3 and 4 of the LocoNet cable. They can be easily made with a crimp tool or connector. If you have a throttle (e.g. DT402) that will short those two wires together for you.
If you are using a BD4 type block detector, make sure it has been grounded (Click here for details).
Make sure your board power supply is entirely independent of any other unit powered on your railway.
If you have a PC interface to LocoNet: download our "LocoAnalyse" software and run it. If you click "discover boards" in the "renumber boards" screen, you should see your DSS1 listed. If not - check your LocoNet cables and power feed. Remove connections to anything else (e.g. detectors) and try again.