Since this machine be for display/occasional use only, I took a gear from a spare 800k and put that in there for now. Works great.
its pretty interesting to see the drive differences. This one is very early: MFD-51W. All the spares I have are MFD-51W-03. There are many subtle differences in eject motor, auto-inject closing arm, etc. I wonder if anyone has all this stuff documented...it’s fascinating to me.