Broken micromotor

I got a load of lego from my cousin, and among this I found a 9V
micromotor (2x2x2 red thingy). Unfortuenately it doesn't seem to work,
nothing happens when I plug it to the battery case (with a FRESH
battery). I measure about 100 ohms between contacts, so it seems like
(at least some of) the coils are intact. The only I've found about the
innards of these motors are
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fail in some browsers). I was able to open the gear side of the motor
(by using a razor blade to gently "tug" out the locking ring, it's not
nescessary to cut away a large section as done on the page). This
motor has a peculiar spirograph-like gear system with a wheel moved by
an off-center motor axle, giving a 2300:1 ratio with just a few parts.
The gears seems fine, but when i tried gripping (with pliers) and
turning the little (off-center) motor axle, it seemed totally stuck.
I've not been able to take apart the coil side of the motor, but it
seems like the problem is there.
Has anyone else had any experience with this?
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These motors tend to lock up under a heavy load. Usually they can be started again by forcing the shaft while energized. I have had the most success using these motors in parallel. An example of this is on this page:
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I have never dismantled this type of motor, so I have little to offer regarding the cause of the lockup.
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Bob Fay
*snip* This sound like the same prob with the 9V MK2 motor. Tyr removing the gear box to see if the motor works.
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