The encoder theory seems plausible to me. This problem started for me right after I had swapped the outer RA and Dec drive assemblies (outer plate with the two drive gears, gear box, motor, etc. and disconnected at the Oldham coupler disc). I was seeking better backlash in RA (that worked). But when I first touched the upper Dec control button on the HC, the Dec motor went into a wild spin at something like 2x Slew speed and would not stop unless I turned off the Gemini 2 power switch.
So in this case, perhaps the Gemini could not immediately read the encoders, since the RA and Dec motors were switched. I tried replacing the Dec cable with a spare and put some dielectric grease on the contact pins to no avail. I also switched the motors back to their original drives, keeping the plates were they were, but this did not alleviate. I also replaced the Gemini battery and reset to HGM defaults, again with no luck. Perhaps if someone unintentionally switches their RA and Dec cables, this could create the same fault?
But as I stated earlier, lowering the slew speed to 600, and selecting Guide or Center from the default Slew on the HC right after start up, then briefly pushing the up and down buttons, seems to have fixed this (for now).? Perhaps a slower initial speed allows the Gemini to better read the encoders and not send a errant motor pulse. I am not an engineer, so I will leave the potential electrical causes to the experts. But these steps seem to be keeping it in check for now. After these initial changes, the Gemini seems to run fine from the HC and from the SGP app for the rest of the night.
Best Regards,?
John
