Alco 260 sound value decoder run awy

[snoopytoo]

My new Alco 260, with sound value decoder, runs at full speed - always!  Worked OK last week when I bought it.  Worked OK last week when I programmed the decoder.  Originally I programmed CV29 = 34, CV3&4 = 2 and address 46.  Worked OK after it was programmed orignally.  Today, I dialed in the address and it took off at full speed.  I had no control.  So, I reprogrammed CV29 = 38 and tried it on my DC test track.  Same thing, full speed.  One more thing, I also tried programming the address as a 2 digit address - same result.  Anybody have a suggestion? 

[Tom M.]

Try a factory resent on the decoder.  Look at the manual to confirm, but I believe you need to set CV8 to 8.  Then cycle the power to the loco.  Check the address, the 2 digit address should be 3.  Try running it on address 3.  If it continues to runaway after that, the motor control chip is toast.  I am not sure what Bachmann's warranty is on this.

Tom

[snoopytoo]

Thanks, Tom but, I had already tried that and it didn't work.  So, I tried again, still didn't work.  Kept at it and finally, for some unknow reason, the loco was back to normal.  One of those DCC gremlins, I guess.  I wish I could list everything I did but, alas, it's not to be.

[jward]

have you tried disabling analog conversion in the decoder? it sounds to me like the decoder was in dc mode. dcc has a constant full voltage on the track, and any decoder which goes into dc mode will cause the locomotive to take off at top speed with no throttle control.

cv 29 programmed to 34 should have disabled analog conversion.