Hard wiring a loco to forward only

[cruikshank]

On our club layout we have a CM&I Diesel, appears to be MPC vintage.  Says made in USA, has one can motor, gears, no flywheel and 2 circuit boards.  One is dead center and lies parallel to the base, the other sits up on it's side and has two power transistors on it.  Because of all the circuitry, I'm assuming the motor is DC.  I need to wire it for forward only.  It has a lock out switch, but it occaisionaly has a mind of it's own, and when it gets the signal to go, it reverses and crashes into the train behind it.  I know where the leads come from the pick-ups, and I see the leads from the motor.  But when I tried to wire them direct, it just chattered.  Any ideas?  Thanks,  Dave

[rtraincollector]

John Electric is your answer . I can tell you yes its a dc motor so hooking them straight is by passing the board to convert it from dc to ac. Now which board is the reverse board and which is the conversion board ( dc to ac ) I'm not sure but if you follow the switch to lock it out I would say thats your e- unit board and the other is your dc to ac. so I guess you need to bypass the board that has the switch hooked to it.

[jprampolla]

Hi Dave and Folks,

     Here is how I have done it:

(Click on the diagram above for a full-size image if it doesn't appear full-size.) 

     If your loco runs backwards after by-passing the e-unit (with a full wave bridge rectifier), just reverse the motor leads.

     All Electronics has a bridge rectifier that I have used: FWB-156W, www.allelectronics.com.

Take care, Joe

[phillyreading]

I bought three 8 amp 400 volt bridge rectifiers from Radio Shack and use them in my three Williams locomotives as one of mine burn out it's circuit board, you may have to cut the leads a little on the Radio Shack bridge rectifier to make it fit in the Lionel loco.   Done it the same way as jprampolla shows in his wiring diagram.  One note; one rectifier per locomotive if rectifier is 8 amp or better, also wiring to the motors from the rectifier is important as it may run only in reverse, if that happens switch the wires coming off of the rectifier to the motor, input side don't matter which wire goes where on the rectifier.

Lee F.