ref: Reply #24

Thanks to Jim Banner's reply (#25) I disconnected the two 1µfd ceramics on loco's pc board and the decoder now remains in control of loco

I installed a DN135D decoder in a new HO Bachmann Spectrum GE 44 Ton Switch Engine.  Decoder wires are soldered to terminals on the engine's pc board (H800X-PCB01) per parts drawing.  At slow speeds (8-12 on Digitrax DT402 throttle) it operates fine.  However at speeds above 15 (a moderate switcher speed)  the decoder looses control, i.e. it won't slow down, stop or reverse unless I lift loco off the track.  Then I can restart it.   The decoder is only connected to the motor, not the headlamps.

I am suspicious that several components on the Backmann loco's pc board may be the cause.  There are two 1µF ceramic disk capacitors and two small wirewound chokes.  There were no instructions accompanying the locomotive recommending disconnecting either the caps or chokes if wiring for DCC.  Has anyone had a similar experience with this or other Bachmann locomotives & Digitrax decoders?