Hey John,
IIRC, you do have to release the inside end of the reversing idler to replace that counter belt (there are two). I'm not sure if it can be done without removing the capstan motor. In any event, replacing them isn't trivial but still not super tough if you time your time and be very careful not to damage the capstan or bend any of the levers that are in the area.
Years ago when I realized that I never really use mine and the belt started to screech, I just cut the belts and live without the counter. In the 3 years since I did that, I think I can count the number of times I would liked to have had a counter on one hand.
