DCC engine starts running on it's own!

[farrellrc]

My GP38-2 with DCC on board starts by itself and runs at full speed. I disabled the analog operation in the CV29 but it still does it. Could this be caused by the capacitors? What else can I do other than replace the decoder with NCE or Digitrax?
Bob

[jbsmith]

Maybe you have an HO Scale model train version of  "Christine" !    [a movie about this  guy and his car]

Could not resist.

[farrellrc]

I sure hope not! But, she was a beautiful car, 1957/58 Plymouth Fury, Red.

[Pacific Northern]

Runaway not caused by the capacitors.

Place the locomotive on the programming track and program CV 8 with 8 (if it is Bachmann decoder equipped). This probably will not help as a runaway is usually a faulty/damaged decoder.

When I added a Digitrax DCC decoder to a Spectrum 2-6-6-2 the engine would move on its own without turning the throttle. It was super erratic, the speeds alternated between slowand fast. Would not respond to direct as well.

Cut the capacitors, engine now runs fine. Super slow speed control, realistic top speed. Pulls all the cars I assign, without slipping.

[Scott823]

Maybe you have an HO Scale model train version of  "Christine" !    [a movie about this  guy and his car]

Could not resist.

HAHA! i just watched that movie!

[Pacific Northern]

Pacific Northern,
I am familiar with the circumstances you describe and a Digitrax decoder being corrected by cutting the capacitor across the motor circuit. In fact, slow movement on its own would have likely been corrected by just resetting CV29. The erratic speed removed by cutting the capacitor. This not the same as a runaway at full speed.

There was nothing slow about the 2-6-6-2, I placed in on the tracks and plugged in the EZ command and away went the engine. Did not even turn the throttle.