It feels as if something is jamming, it might not be gears but the rail on which the front element rotates/extends. Hard to know exactly. I did a search it doesn't seem to be common at all, but I did uncover this:
https://www.dyxum.com/dforum/minolta-af ... 05906.html
Nobody replied so I assume it's uncommon. It does feel like it's jamming, as if something is blocking it at times. Move the lens around a bit sometimes releases it, so I'm guessing something has dislodged. When it was working I did notice a slight screeching sound at the infinity mark as if it was metal on metal contact (not gear sound)
Another post here where someone dropped it and damaged it
https://www.dpreview.com/forums/post/33910696
It was working so my money is on something in there sticking the sliders or mechanism. It hasn't had any damage and it was working initially, but as the camera tech guy said it's not been in use for a good while, that might have moved something around who knows
It is unique I've never seen rendering this good on a zoom lens in that range, nothing I've seen from modern lenses seems even slightly close, they look somewhat clinical to my eyes (some are nice but never to this level). That contrast, smoothness is not something you see often, and it holds it right out to the edges even wide open. There is little to fault some slight CA at times, nothing dramatic mostly. Optically it's something special IMO - hopefully I'll get something sorted