Hi Garyth64, I have the same mount, a second hand purchase from many years ago, happily takes my 8" Newtonian, and luckily it is nice and smooth on both axes. It came with the original Meade 6" Sonotube but I drilled through and mounted the dovetail saddle when I got the 8" as finding larger straps was impossible. This is easily removed for when using the Meade
Not so lucky, the motor never worked from day one. I tried on and off over the years, recently found a replacement power IC and re-soldered it to the board and got the motor running but there is no regulation on the speed, the motor spins way too fast, I estimate it will do a full rotation of the scope in about 51 minutes.....
Not knowing enough about electronics my dabbling goes no further.
I can rig up a bracket to mount a new motor to the existing gearbox, and I have a speed controller that I can put to use, what sort of rotation speed is needed to drive the worm gear?
I used the speed controller on the existing motor and at 4% on the speed controller the motor turns at approx. 600rpm, the worm gear then turned 1 revolution in 1min 54seconds.
There are 144 teeth on the main axis wheel, so if 1 revolution of the worm gear turns the wheel 1 tooth, 1min 54 seconds x 144 teeth = 1 axial revolution in 4.8 hours.
if the axis needs to turn 1 revolution in 24 hours to track objects then 24/4.8 = 5, meaning I need a motor that turns at 1/5 of 600rpm = 120rpm.
The no load speed of the original motor is 2700 rpm
Do my numbers make sense?
Any advice on what sort of motor would be possible to substitute, I guess if at 50% on the speed controller the motor turned 120rpm, that would be ideal as I would have the range to speed up or slow down the motor.