Ive never messed with it or have seen it but i would guess its a timming problem with gears and switches. It could also be a surface mount fuse that controls the motor that drives the gears. I have an A510 and i can see problems with this thing. The lense going in and out when it starts ive had my hand infront of it as its powered up and it pushed my hand out of the way.
Dropping it on the lense i can see this being a problem.
I think what im going to do is get that lense filter adaptor and install that as a protective cover over the front. I think this can not only help keep dust out but also work as a shield around the whole mechanisim that seems to be the #1 problem with this model.