I've come across these a couple of times, but both times some of the internal plastic cams and parts were cracked or disintegrating, and the machine could not be saved. Folks talk about having cogs 3-D printed and so forth, but I'm not sure it's really worth it (personal opinion there).
Sadly, if it was me, I probably wouldn't waste time on it, but consign it to the metal skip.
Maybe other folks can give some more positive views?
Best wishes
Leila