Help Needed

[DocGeoff]

I have two Intermountain F7's with Digitrax decoders. They have run beautifully since I installed them. However, last week one of them stopped. No motion. I re-programmed the decoder and now the unit runs at full speed at 2 on the controller, forward or reverse?
Before I remove the shell what does anybody think?
Is it a bad decoder? Maybe a short? On this particular unit I did't install the lights since I am running them back to back close coupled and didn't want to have to connect the tiny wires to the decoder. Once was enough!
Any help will be appreciated,

[wendell camp]

Do you have the analog  in the decoder disabled some times after a short the decoder see dc signal before the dcc signal and take off at full at full speed. HTH Wendell

[dclyde]

You said you reprogrammed the decoder.  Did you start with a factory reset?  If not, I'd do a factory reset and reprogam the decoder from there.

Dave