Tomytec TM-18 power unit failure

I just got the Tomytec TM-18 power unit from Japan to adapt for an old model train set that had no power unit. Gave it a quick test on the track for about a minute, and it worked great. With a little modification it fit nicely to the old train. I gave it another run on the track, and in less than 5 minutes it started to hitch, jerk, and then stopped.

The motor had seized and the plastic housing melted.

When the whole motor was dissembled, there was a gray plastic/hot glue material on the armature. So I scraped it off, and cleared it out of the motor. After reassembly the unit again ran great, for about 3 minutes. Then it slowed, and stopped. This time with a little bit of smoke. Took it apart again, and found more of the grey plastic in the very back of the motor.

The little grey blob behind the armature is what came out of the motor

With all the grey plastic cleared out of the motor, once more assembled to try again. This time when it ran, there was very little torque or speed. And again it didn’t run long, maybe 30 seconds before the stopping and smoking.

So what happened? I’m making a guess here, but I think it’s likely a short in the armature. The grey plastic goo that I cleared out of the motor was probably some kind of spacer or bushing inside the motor. When the armature shorted, it heated up and melted that plastic internal part. Can’t find any diagrams or photos online, so may never know what the grey part was.

I’m calling this one a write off, as there is no fix (that I’m aware of) for a short in the armature. I ordered a replacement unit, and hope to have better luck. And just because I can’t let things be, also ordered a couple of cheap motors on eBay to experiment with.

Converting a Tomix n scale train coupler to Arnold/Rapido

 Bought a really nice new n scale train car from Tomix to run with my 25+ year old KiHa trains. Just getting back into model trains after all these years, I assumed that not much had changed. Boy was I wrong. Over these years the old standard Arnold/Rapido coupler has been disappearing on new model trains in favor of smaller, more prototypical, and nicer looking couplers. 

Tomix body mount coupler on the left, old Rapido on the right.

So my dilemma, with the nice new train car, became how to run it with my vintage ones. Tomix seems to offer a replacement bogie (train wheels) with the old style coupler, but that would mean ordering from Japan with $20 postage for a $5 part. Not an option now, and I’d rather not wait to piggyback on my next order whenever that will be. The only way to go seems to be to remove the Tomix TNs body mount coupler and try to fit a Rapido to the bogie.

Rapido coupler glued onto the Tomix bogie.

I ended up gluing an old Rapido coupler onto the Tomix bogie with epoxy. Works great! So great that I might just keep it this way.

Glue up on the left, an old car with original coupler on right.

So that’s about it. Seems to run great, so I’ll keep it this way until I decide to either update all the couplers or get the actual part from Tomix.