Just to share some good news!!!
I'm overjoyed with the results of fitting a Meade # 493 DS motor kit ( comes complete with # 497 Autostar controller) to an older TV Systems GEM. This mounting is similar to the Losmandy GM8 and has 180:1 worm drives.
All you really need to know you can get from Mike Weasners site (
www.weasner.com) there's a great article by Chris Erickson which is a MUST read.
I made a couple of amendments to his suggested method:
1. I retained the bearing in the front of the motor ( see photos) to "close" off the motor housing and allow me use use part of the plastic moulding to locate and hold the motors on my mount.
2. I found by cutting the worm section ( That broke my heart... never like doing things to precision worms!!) and holding the worm in a drill press I could file the worm portion away ( gently!!) to get an exact 7.00mm diam shaft.
The couplings were drilled to suit ie 7mm for the old meade shaft and 7.5mm to suit my drive shafts on the TV.
Whole thing including cutting the small plastic box for the connections, making up a #505 cable only took 3 hours!!!!
Very easy and VERY VERY effective!!!!!
I'd recommend it to anyone with a small GEM who would like to GOTO etc.