Mr Osborne, my experience is contrary tp your speculation regarding blade stall. I've had it happen in turns of both directions, and vigorous but not terribly rapid roll rate or exceptionally high speed- well within the green arc and low DA. The surest way I've induced it is cruise or higher, pull some g, and roll. The stick just stops, lateral. I'd hate to force it, as the onset is sudden and unpredicted- it could well cease with me leaning on it- That would introduce new and exciting issues. Pitch reduction (both senses of the word), slow, and the aircraft's normal again.
As to belts- An Arizona 350 had an air conditioner compressor drive belt break and take out the hydraulic drive belt, too. It's a chintzy system in an otherwise very satisfactory helo.