Скачать или смотреть Repairing a Lego Duplo Train

Pushing the train did nothing. So how did I fix it?

First, I tested it using the app: https://play.google.com/store/search?...
(Hint: If you're experiencing Bluetooth connectivity issues, try clearing the app's data and cache, then restart your device.)

It turns out the train base had two issues:
1) The motor had poor internal conductivity. I disassembled it and cleaned the split-ring commutator.
2) The motor's polarity was wired backwards by the manufacturer—and somehow it passed quality control. I re-soldered at the motor terminals to try to keep the circuit board looking nice.

Before reassembling, I highly recommend re-greasing the gear mechanism for a smoother operation.

Finally, apologies for all of the grammatical errors in the video—it was a one-take recording. And yes, I did end up put it all back together again. :)

Good luck with your repair!