Cosmic Clash not working

[Hobie-wan]

Hello HHM people. I did a search first, but the only other CC repair thread was one from 2007 about wiring. Hopefully I haven't missed something posted previously and someone will have some insight.

I have a Cosmic Clash that I'm trying to fix for a friend. Hopefully someone with a working one that's already been sliced open might have some ideas. When powered on, the game runs and the film with the ships rotates properly. If you push the fire button, the 'firing drum' rotates as far as the button will push it. But it never seems to 'fire'. If I turn the drum by hand, the record plays noises that seem to be appropriate.

I briefly opened up the gearbox and looked for any broken teeth or if I could see any gears that were simply spinning on their axles, but didn't notice anything that looked wrong. To me it looks like the worm gear I've pointed to here should catch the teeth on the drum to spin it, but that never happens. Anyone have any ideas?