I have acquired a Bachmann GE 70 Ton DCC switcher. It runs poorly. I've disassembled it to the point where the motor is only turning its flywheel --both fore and aft drive shafts disconnected. Using my NCE controller, as I increase speed, the motor just hums/vibrates loudly for the first two-three speed notches and then begins to turn around the fourth speed notch --and continues loudly. Is this a DCC decoder issue or a motor issue? It is really unusable in its present state --runs like a cheap, bad toy and not a representative model.
Update --if anybody cares. I didn't get any responses and calling Bachmann just pointed me to resetting the decoder (setting CV8 = 8), which I did; no joy. I had an old Digitrax DZ 126 laying around from an earlier to-sound conversion, so I removed the Bachmann factory DCC board and soldered in the DZ 126 --works fine; no vibration/hum, no sounding like a bad toy!!
Glad you got it working! I've had mixed luck with various decoders, and seldom have gotten to the point of changing one out in the hopes of getting a loco to run better. I'll need to remember this when all else fails...
Bill in FtL