Animations Not Synced Properly

[aibo7m3]

Hi everyone! I currently own five Teddy Ruxpins and two Grubbys that are all thrift store/flea market finds. I purchased my newest Teddy Ruxpin as untested at a flea market this past weekend and managed to get him mostly up and running, but he still has some issues. He plays tapes and his lower jaw and eyes move, but he is still unable to move his upper jaw and his animations are not always in sync. He sometimes moves his eyes erratically instead of blinking naturally and while he always "speaks" during his own lines, he will also sometimes "speak" during other characters' lines too. This occurs on multiple tapes and my other Teddy Ruxpins do not have the same issue on the same tapes. If I connect Grubby to him, Grubby will also be out of sync. Any idea what might be causing this?
Thanks in advance!

[illiopmom]

It could be the cassette drive belt. As it stretches out of shape over the years, it often causes Teddy's animation to be sporadic and incorrect. Since it's the cassette belt, it also distorts Grubby.

As for the upper jaw, I would keep moving the jaw as he speaks. It could just be really stuck. If not, you'll have go inside his head and see what's up.