Service mainspring only?

[Laser145]

Question about service.

My moonwatch has a broken mainspring (I think). It winds until you hear an audible skip inside the movement, then keeps winding. Keeps time ok now, but power reserve has gone way down.

Until I broke it the watch was winding smoothly, running perfectly, etc.

Took it to an NYC watchmaker and they would only do a full service... but what if I just want this one problem fixed for now?

Is that possible? bad idea? any recommendations in the NYC area?

Thanks

[SearChart]

The whole movement needs to be taken apart. Full service is necessary.