The Sony MZ-R909 (late 2001) is the next-iteration on Sony's MZ-R900. No more dual jog levers since it now had a d-pad and a right jog wheel.
This one came to me courtesy of a YouTube/Discord user that had an interesting issue - the lens had fallen off!
Gluing the lens back didn't work so I tried replacing it with a Sony MZ-R900 laser. It seemed OK, but even after some tuning in the service menu, it wouldn't read consistently. I then swapped it with a "dead" MZ-R909 laser and that didn't work either. My last chance was another junk MZ-R909 I ordered but even that didn't work - so there was probably something wrong with the red unit's board or motor.
I was able to get the user a working model by doing a "shell swap" so check out the video if you ever need to get in and out of a Sony MZ-R909!