Yup.
Small motors can drive you nuts.
Mark a segment ,then go over with multimeter on ohms or a series lamp off a battery.
Should be able to pick up opens with this method.
Another easy test is to connect a power supply on low volts while all but stalling motor with your fingers.
Rotating shaft with your digits will let you know where any dead spots are.
Chances are motor turns and stops on dead spot.
Bloody things!