Motor problem...a little help please

I placed a similar post under equipment, but I didn't get much response. Thought I would give it a try here.

I have an older 8" Meade Starfinder (pier mount, metal straps to hold OTA). I took the scope out 2 nights ago, flipped the switch on the motor and it started with the following pattern:

It goes "Whizzzzz. Pause. Whizzzzz. Pause."

I have replaced the batteries and jiggled wires, but I cannot get it to run consistently. It does appear to turn the gear, but in a start and stop pattern.

What is the fix for my problem?
The number on the motor reads RF 500TB 12560.
Am I looking at replacing this? Must it be replaced with the same motor, or do I have options?
Where would I acquire parts?
Recommendations?

Thanks,

Dave

Dave, That is what it sounds like when the spur gear is meshing too tightly. Loosen up the meshing of these gears, and see if the problem is still there. It may even be that the worm is meshing too tightly, or bent. At any rate it sounds to me like any rhythmic motor sounds would have to be due to a varying load on the motor. I found this site useful in adjusting the gears on my vixen mount. http://www.astronomyboy.com/cg5/dec3.shtml#adjustments