TMCC C420 sound problems in conventional mode

Sounds like the RS board is seeing a DC offset and ringing the bell, or the board got damaged in the process.  In command mode, the RS board ignores any conventional track voltage whistle/bell commands.

Have you tried a different transformer?  Could it be the CW-80?

John,

I have not tried another transformer as my layout is powered with 2 CW80s for the two main loops and another for accessories. I do have a spare Z-750 so I will give it a try on a test track and let you know. This loco has never had any issues with the CW80 before. 

Jay in Ottawa

Ok so I tested the loco on my elevated loop which has a different CW80 and it had the same problem. I also tested it with the Z-750 and the same thing again. Something is amiss with the loco in conventional for sure.

I am trying to think if I moved something that could be causing the issue when I took it apart and reassembled it? I know I had to remove some tape along the bottom of the rear handrail that seemed to be there to insulate it but I replaced that tape with new electrical tape during reassembly.

I'm not very electronics savy so I am not sure where to look on the inside of the loco. Let me know if any pictures would help.

Thanks,

Jay in Ottawa

Well, at this point I'd try another RailSounds board.  If you have a different locomotive, you could try a swap, just to see if the issue follows the board.  You're obviously seeing a DC offset momentarily that is triggering the bell function.

Did you put this on a short piece of test track and see if it does it there?  Maybe something odd is happening on the layout?

If you haven't done so, try re-programming.

Bill

John,

When I tested it with the Z-750 it was on a short test track and it had the same issue.

Bill,

Will a reprogram help if the issue is only in conventional mode?

Thanks

Jay in Ottawa

Reprogramming can't hurt, and it's cheap to try.

Tried reprogramming....no luck. Any other ideas? Is there something I could look for that might cause issues with the board? Is there any potential that when I reassembled it I missed insulating something or a wire is touching the board?

Any suggestions would be appreciated.

Jay in Ottawa

Check the motor lugs/leads carefully, to be sure that nothing is touching the metal motor casing.

Chuck,

Sorry but I'm a novice at this, what do the motor lugs and leads look like?

Thanks,

Jay

Where the wires connect to the motor.

Try it without the cab, you could be pinching a wire or the body could be pushing on the motor wires as Chuck stated. If it still don,t function properly try swapping the RS Power board from a working engine.

Bill

Bill,

I ran the enginge with the shell off...no change. I am hesitant to swap boards as that is outside of my comfort zone and I don't want to end up wrecking one of my functioning locos.

Anything else I can try without digging into the boards?

Thanks,

Jay in Ottawa

Did you physically check the wires at the motor, so no strands of wire are touching the motor case, or the motor lugs are not bent over and touching? Also I believe this engine has LED headlights. Did you remove them when you repainted the shell? Any pinched wires at the headlights and/of marker lights? The lighting circuit could also be the source of the problem. Did you disconnect the lights when you tried the engine with the shell off?