Lose the PowerMaster, you don't need it with command controlled equipment. Just connect the U terminal on the command base to the outside rail of the track, fire up your transformer with the engine on the tracks, you're good to go.
Note that you may have to set the TMCC ID of the locomotive, check the ALCo PA A-A Diesel Loco Set - 8/03 User's Manual for instructions of how to set the TMCC ID.