Do a search to see if meaningful internal spares for that model are available in the first place.

Then start carefully dismantling, probably starting by getting access to the drive to the blades.

Make drawings and written notes - maybe even photos. Don't trust memory.

Look and think

You should be able to work out how it works and what has stripped, what gear just spins on its shaft when it should be solid drive, etc.

You'll then have an idea what you need to order.

Personally, given the low cost of these, I'd just get a new one with a warranty.

Dkdj
October 2022