Seatool ND30 focus/zoom gear

Hi, would like to know if anybody alse have experinced the following and what the fix for it is.

If I turn the outside knob, the gears spin correctly. Also if I try to keep the gears from spinning, it takes some force to do so. However if I load my camera and the try to zoom the lens the outside knob turns, but the inside gears don't move. The metal bar inside the first gear turns but its just sliding inside the gear and so the gears don't move.

Hoe there is a easy solution.

Thanks

Possibly a loose set screw in the gear? Does the shaft have flats where the set screws should bear? Maybe a misalignment there.

I haven been able to see a set screw, think its part of the problem and not the best design solution for this kind of application.

I will try contact the manufacturer for a solution.