This is in all likelihood a 12V or 6V DC motor. If that's the case, try to check any RPM marking on the motor. If matches, try replacing with a cassette player motor.
Sudhin-> Electrician says its not possible to replace with cassette player motor.
There is probably even a centrifugal switch control on the board to control the speed of the motor, hence some speed difference may be compensated from the onboard controller and the controller on the new motor itself. That should be the cheapest and most reliable solution, given it clicks.
Sudhin-> Any idea where a spare motor for this model available?
Edit: You will need to get the stepper gear shaft swapped to the other motor.
Regards