Think I recall Takahashi a while back had a notification on their website that the source for older mount motors (pre-Temma m) had ceased and where no longer available.
There are these options though......
Astro electronic replacement motors plus FS2 controller
http://www.astro-electronic.de/em200.htm
SS-one KODO
https://digiborg.wordpress.com/2017/...s-one-project/
https://www.sciencecenter.net/hutech...moteAccess.pdf
K-astec E-Zeus systems, need some google translating
http://k-astec.com/contoroler(AGS-1X).htm