Atlas SD-35 DCC will not run

[casmmr]

I brought 2 Atlas SD-35's with DCC NCE decoders.  I placed them on my program track and they accepted the new numbers.  I placed them on the layout and they sat there with the front light on, would not run, nor would the light go out.  The light would not change directions just the front light would stay on.  Any suggestions?

[mu26aeh]

Take shell off and press down in center where contacts are.  Apply power to rails.  If engine runs, probably have to reposition motor contacts.

[peteski]

If the light is on but you can't change direction then there are more problems than motor contacts. The light shoudl be controllable, even with motor disconnected.

First of all, what DCC system are you using?  When programming on programming track can you actually read CVs out of the decoder (rather than just programming them)?  Can you read out both short and long addresses? Can you read CV29?  What is it set to?

Do a factory reset on the decoder then try it on short address 3. At least the headlight should properly respond to the loco's direction and F0 state.

[casmmr]

I use the Digitrax Zephyr system.  When I went to change the address it read 0000.  it took the change to 7422, and when you try the read address feature it reads 7422.  I checked the motor contacts and it appears that they are in contact.  I do not know how to read the cv29.  I can try and see if any club members can help on Tuesday.

[C855B]

I had very similar symptoms on a TCS when (as it turned out) one of the motor contacts wasn't isolated from the frame. It would light-up, program and read back, but wouldn't control the lights or run. Might be worth another look.