emergency: sp1000 advance sprocket is hiccuping

[fish4570]

cost me a roll of shots. about 3/4th an inch of each print was double exposed. i lightly held my finger against the teeth, and advanced the wind lever. the sprocket hesitated about two teeth worth, then the shaft turned as it should. i could see it was doing the same thing when i tried to load another roll. it just would not advance properly. i sure hope this is an easy fix ...