There is a problem regarding programming the DP2X when installed in a Atlas AEM7 locomotive. Why?
The number board lights of the locomotive are connected directly to the track. They are not in the decoder circuit and are not under control of the decoder. This was a oversight on the part of Atlas. The problem is the current draw of the bulbs interferes with the programming operation on the programming track. The programmer sees the constant current draw of the bulbs and cannot differentiate between the bulb current and the decoder acknowledgment current. It makes it impossible to read or write to the decoder on the programming track.
What is the solution and how can I program the DP2X?
To do your initial programming of the decoder plug it into another loco. Program the desired address, speed table, configuration, etc., then plug it back in the AEM7. Future programming can be done in ops mode on the main track. Programming on the main is not affected by the number-board bulbs. You can use ops mode programming at any time with the decoder installed in the AEM7. The only CV that cannot be changed on the main track is CV1. TCS decoders do allow programming of CV1 in ops mode but most command stations do not allow it. Easy DCC is the only system we are aware of that will allow it.