Large Scale Central

Split-Jaw Reversing Unit Mystery?

Problem Solving
#1

Question:
How can a USA 4-wheel motor block, powering a Northest Narrow Guage kit trolley, on 60’ of track with the Split-Jaw Reversing unit, run successfully up-and-back completing the timed pauses at each end?

Problem:
The trolley runs fine to the point of the diode in the track and then continues at speed and overruns the track ending without any pause.
By comparison, all of my LGB, USA, and Hartland locos, 0-4-0s included, have absolutely no problem with the same section of track and the same 13 volts of power. They all make the run, pause at the ending, and then make a return run for endless hours of run time. The Split-Jaw product has been without fail.

Analysis:
Here’s what I have tried so far –

  1. I ran the unit on the layout that does not have the back-and-forth reversing unit. It ran fine. No problems forward or reverse.

  2. I removed the motor from the motor block assembly - a MRS545SH USA motor as a complete motor block was included in the trolley kit - and replaced the motor in the block with a 14 volt light and pushed it on the track by hand across the diode, after crossing, the light went out, there was a pause, and then it went on again for the unit to return to the other side. I even ran my GP 38 which has the two of the identical motor blocks and it worked fine, pausing and reversing itself. No problem with the Split Jaw product.

  3. Then, after removing the motor from the block assembly, I hooked up ONLY the motor with short wires and aligator clips and after insulating the motor from the track, I rubbed the clips along the track for continuity. The result was the when crossing the track gap and diode, the motor stopped, paused, and started again in reverse for the “return trip.” Obviously, it was not the motor.

  4. I ran a Hartland “Mac” 0-4-0 switcher just to be sure, no problems whatsoever.

  5. I throughly checked all the motor connections, reinstalled it into the block, and tested it with a bench power supply. It runs fine. The gears are lubed. The wheels are not binding. The motor is, I think, a Mabuchi (there is an M on the motor can) and it is beefy – just as the GP 38 motors. The track “shoes” move up and down freely. As I noted in #1, the trolley runs fine on the rest of the layout.

Any suggestions? I am stumped.
Thanks,
Wendell

#2

Try reversing the leads on the motor. soundslike it may have been wired “backward”. Quick test - put the trolley and the GP 38 on the same length of track - do they run the same direction together?

#3

Steve is on-target! YES! Thanks to his suggestion, reversing the wiring to the motor did resolve the problem. How, is not in my vocabulary. No matter, his suggestion works – the reversing mechanism now works.
Hopefully, for any who also make a scratch build or from plans, you will have this information if a reversing unit problem.
Thanks, Steve.
Wendell

#4

Your most welcome - glad that it was a simple fix.