I picked up a Gizmo Furby from a toy fair for £20 and the person who sold it to me said it was "a bit temperamental".
I took it home and it wasn't really working at all, it would start up, and then freeze in place and just make a constant buzzing noise, no matter what I did. It had some battery acid that had leaked inside the terminals that I have removed as best as I can.
I skinned it to wash the fur and take a look at it, and I stripped a screw at the top of the head where the little upper brows are.

I sawed it down the middle to get the upper plastic parts off, and then I was finally able to take the shell off to take a look, and apart from being a bit dusty, everything seemed normal. I've been spending the entire day spinning every single gear, I've used vinegar to remove all traces of acid or rust and the batteries seem to be making contact, as the furby motor is loudly humming and buzzing, and it occasionally moves and then stops.
I have messed about with the sync screw a bit and after tinkering with that for a bit, the furthest I have gotten to see the furby working is it just looping it's start up dance, I'm assuming it's trying to find the home position, but despite all the playing around with the sync screw, it hasn't changed.
It keeps fluctuating between being completely stone dead, then humming and buzzing, then looping in the Dance.
I have no idea what the heck is going on tbh lol, and I really wanna fix this guy, is his motor dead/failing, or am I just missing something? I don't think it is the motor because its spinning and humming, and for a split second he started talking, and them went dead again.
Any advice would be massively appreciated :)

Please Help with Gizmo Furby