I seem to keep collecting other people's old cast-off German equatorial mounts only to discover why they got rid of them in the first place. Not having the heart to lumber some other unsuspecting amateur with their various problems they have just accumulated. That was until I had the opportunity to use John Gleason's Paramount at Steve Lee's in Coonabarabran.
In my opinion the Paramount is one of the best available but I was not prepared to pay the high price they go for here in Australia. The experience of the Paramount sent me looking for methods to make my existing mounts goto. After running up a few dead ends trying stepper motor and Meade based conversions I found the SiTech and have not looked back. I have even encouraged a couple of friends to convert their mounts and so far they seem happy with the product.

So far I have converted two mounts. The first is an early Losmandy GM-200 which also needed to have the tangent Dec drive replaced by a worm and wheel. The second is the original Vixen Atlux. This appears to be rare these days. It was an early goto but as the maximum slew speed was only 64 times sidereal and external encoders can't be fitted, it was very impractical.

The GM-200 Dec worm pivots and is spring-loaded to allow for irregularities in the old worm wheel and to remove backlash. The original stepper motors of the Atlux and GM-200 have been replaced by Pittman 9000 series servos. The GM-200 motors have 19.7:1 gearboxes and timing belt  reduction. The Atlux motors have no gearboxes as the mount has double worm/wheel internal gearing. The small black boxes on the RA and Dec drive housings protect the motor encoders as the Pittmans are much longer that the original steppers. The boxes and new connectors on the control panel are the only external signs of the conversion. The Atlux uses internal slip rings for the drive wiring and these were used for the encoder and motor connections.

Losmandy GM-200

Vixen Atlux