9v motor won't run on straights

[skinkfem]

Greetings all

Recently i bought an used 9volt motor on Bricklink that is showing a problem i havn't yet encountered, or even heard of for that matter.

The motor refuses go on a straight track. At first i thought that i had put a to heavy test-train on the motor and tapped it gently from behind to see if i got any reaction from it.

I was rather surprised when it jumped to action as soon as it hit a curve, only to stop again at the next straight track piece.

Building a loop containing only curves i was able to pull the main model of 'Hobby train' and the 2 'Mearsk' cars for some 30 mins without any problems whatsoever so the motor obviously isn't

weak.

I guess the Lego curves are sligtly narrover than the straights and that's why it looses connection.

Have anyone else run into this problem and figured out a solution?

Could i use it in tandem to a normal motor to pull the 'Santa fe' for example and let the flawed motor drag on the straights or would such actions couse one of the motors to burn out?

Would be greatful for any help.

Regards skinkfem

[Spitfire2865]

It probably is the electrical pickups on the wheels. The 9v motor has sprung metal flanges and that probably was damaged somehow. I can't really say what to do but don't use it with another motor. You don't wanna risk burning out a working motor just for some extra pulling power in corners.

[skinkfem]

Thanks for the quick reply.

If there's no way for a newbie like me to fix the motor then i'll just have to ask the seller for a refund.

It might be a good idea to tell him to test his remaining motors on straights as well.

Regards skinkfem

[kieran]

Thanks for the quick reply.

If there's no way for a newbie like me to fix the motor then i'll just have to ask the seller for a refund.

It might be a good idea to tell him to test his remaining motors on straights as well.

Regards skinkfem

Have to agree it does sound like the pickups, before sending it back take a close look and make sure the 4 mettle discs on each wheel can move Greeley toward the motor body and back out again, you may find a bit of fluff or similar is stuck preventing the flanges making proper contact with the conducting rails

[skinkfem]

The area between the motors body and the metal part of the wheel are clean.

However looking closely i now see that the rubber outside the metal part of the wheel are worn on one side.

I guess this would make the motor tilt and the metal pickups get to far away from the straight tracks to recive any current.

I guess thats it, thanks for the aid guys.

Regards skinkfem

[Lazarus]

OK i can think of two things that might be the issue.

1. metal wheels are very durty around where the flange is hiting the track. proberly not this one oddly 9v motor wheels dont really get durty.

2. on all 4 wheels there is a copper/brass plate that presses on the rear of the wheel to transfer power from wheel to motor. This can get dusty and durty, its not that hard of a fix. You just need to open all the motor take the wheel axle out and get a achol swab (any sort of clean stuff should be ok) and clean the copper/brass bit. Also before puting it all back together if you bend the copper/brass but out a little more it should apply more pressure to the wheel and give you a 100% contact.

Open motor

Take out wheel axle only.

Clean bush type pressure plates and bend out slightly.

[alainneke]

Does anybody know where to get replacement rubber bands for these motors?

[Lazarus]

What about the rubber bands of the PF motor wheels they are common and anything i would think they would be the same size.

[detjensrobert]

Sorry to bump an old topic, but ive had a similar problem. One of my 9v motors works perfectly, but the other "jitters" on straights. It jerks or lurches forward (if that makes any sense). The gap between the flanges and the motor is clean, however, the spring that pushes on the flanges is slightly weaker than the ones on the other 9v motor. Has anybody else had this problem/knows how to fix it?

Again, sorry to bump an old topic. I didnt want to start a new one when I saw this one.

[legoman666]

I use stiff phosphor bronze wire to solder new contacts on the original nickel silver contacts. If you mail it to me, I'll do it to yours for a small fee.

[Lazarus]

May also be a sign of the motor bushes going.

[detjensrobert]

True, but it runs just fine on curves (and straights if pulled). I'll see if I can scrounge up a video to show you guys.