When you say you've hard wired the NCE decoder, do you mean, to the lighting board, or you've bypassed the lighting board. What I have done for quite a while now in both sound and a couple of silent ones, is remove the stock DC lighting board altogether because all of the functions etc are on the decoders anyway and the lighting board is basically just extra baggage. The only problem that presents, is having to extend the pickup wires (at least from 1 truck) to join up to the single pickup left/right track wires from the decoder.