Monorail 6991 Motor Help, please

[izmo97]

We have inherited a complete Lego Monorail 6991 set, that was carefully packed away and stored for the last 20 years. Last time it was used, it was fully functional. Now that we have set it up, the motor won't work.. Battery box and light is still working. Have inserted a brand new battery. My question is - is there a way to service or fix the motor? I have spent hours googling, but have not come up with anything. Thanks heaps for your time, Izzy

[leafan]

Might be a silly question, but have you pressed the little direction button on the base of the battery unit to either the left or right side?

If it's centred the train won't move.

[izmo97]

Yes, unfortunately no movement. 

[Jetflap]

If the motor is truly dead, the easiest option is to buy a replacement on Bricklink or eBay, but these motors are very tough and i have never had one fail yet so I have personally not tried to open one. The wire between the battery box and motor can fail quite easily however. Have you checked the continuity of the wire? You can easily touch a battery directly to the motor to take the wire out of the loop. See photo below. Also, can you easily turn the metal gear on the bottom with your finger?

 

IMG_20190429_194529025 by jet_flap, on Flickr

[Unfinished_Projects]

I second the notion of looking into the wire. They get very brittle with time. I too have yet to see a broken monorail motor. When checking the wire be sure that all connections are clean.

Good luck fixing your monorail! Warning it may get expensive if you enjoy it and choose to expand!

Unfinished_Projects

[izmo97]

Thanks so much for your replies. I have connected the wire to battery box and light and it is working fine. I think I will invest in a good electronic spray cleaner and take it from there. The metal gear on the base has good movement.

[izmo97]

I am happy to report that after investing in a bottle of Electronic Spray Cleaner and the motor is running now :-)
It is only going in one direction though, i.e. when I push the black pointy bit out on one side it runs, but when I push it into the opposite side it doesn't. Any ideas here?

[Jetflap]

Glad to hear you are making progress! A couple other things to try:

With the 3 position switch in the position the motor is now running, try flipping the 2x2 wire connection 180 degrees. This will make the motor (as witnessed by the metal gear) spin in the opposite direction. See photos for clarity. If it does, I would say the problem is most likely the switch. Perhaps you live near the ocean and dampness or salty air has corroded some of the metal in the switch. This seems plausible as with some cleaning you have restored some function to the motor. You could try sliding the switch back and forth a bunch of times quickly to wear through the corroded film on the metal and try it again.

If that doesn't work I would still try the battery directly to the contacts on the motor as mentioned in my previous post if you haven't already. Just to 100% easily eliminate the wire as the problem. It's still possible there is a wire issue even though the light works on the wire. The light uses 2 upper contacts, the motor uses all 4 of the lower. Could be a short or corrosion in there affecting it. It's unlikely but it would be nice to be sure.

IMG_20190501_100124196 by jet_flap, on Flickr

IMG_20190501_100140979 by jet_flap, on Flickr

[izmo97]

Thank you so much for all of your help. It is now working perfectly :-)