I recently had my RT-909 serviced. It had sat idle for about three years. The pinch rollers and capstan drive belt had to be replaced and the capstan motor had a dead spot, so it was replaced, too. The tech charged me $150 for the capstan motor, so that would seem a reasonable price. Be aware - the tech was using a 1996 PRB belt cross-reference book and there is a typo in the book. The correct capstan belt is a FR14.5, and not a FRX14.5. The incorrect belt is 2X the thickness, but correct circumference.
Nando.