This is my DS10 mount. I purchased the GEM head around 1990. I had the mount rebuilt with new taper bearings in the top and bottom of each shaft.
 I had the old RA drive moved over to the Dec shaft. I installed an Opticcraft 6.6" drive on the RA shaft. The mount has a Losmandy saddle plate.
The mount has an AC synchronous motor on the RA drive and a 12v DC motor on the Dec drive. This mount has proved to be very rugged
and can easily carry my 10" SCT OTA. The GEM head sits on a 4" diameter thick wall aluminum half pier, which in turn sits on a HD steel tripod.
The RA drive has 203 teeth and has about 18 arc secounds of periodic error over a 6.7 minute period. The clutch is very well designed. I am
pondering the fate of this GEM. I might convert it to GOTO using the Bartels stepper system or I might sell it as is.

Here's some links to images of the mount:

Front View

Side View

Rear View