I have an odd issue with a TMCC conversion of a Lionel Speeder. I'm using the ERR MiniCommander ACC (with ENG code), a special order from ERR. I've used these before in other small motorized units, and never had any problems.
When I run it forward, it runs very rough until it's running pretty fast, however in reverse it runs smoothly right down to stopped. With the conventional reverse board in the unit, it ran fine.
Things I have done to isolate it.
- Ran the chassis on the track with just a diode between the motor and the pickups. It runs fine at any speed. Reverse the diode and it runs the other way fine as well.
- Inspected and lubed the gears, that all looks fine.
- Ran the motor by itself on the bench from a bench supply. It runs smoothly right down to dead slow in either direction, and it draws the same amount of current in either direction.
- Did the same thing with the motor in the chassis on the bench, again, it runs fine in both directions at any speed.
- Connected the ERR MiniCommander back up. Wired a 1uF NP cap with a pair of 10 ohm resistors in the motor leads to provide a noise filter for the motor to see if that would have an effect.
- I put the unit on the bench on a set of test blocks, and wired the track voltage directly to the board, bypassing any possible continuity oddity in the pickups or wheels. It still has the problem in forward, no problem in reverse.
- I connected the motor directly to a DC supply while on the test blocks, the motor functions perfectly in both directions with the same current draw at slow or fast speeds.
- Swapped out the ERR MiniCommander board to eliminate that as a possible issue.
- Just on a total lark, I dug out my CAB1/command base and used that to run it, same result.
I'm at somewhat of a loss what is going on, I've run out of ideas. Anyone have some insights about what might be happening?