An f/8 315mm in a 2.1m dome? That really is tight. Did you add tube counterweights to balance at the midpoint? How frequently did you need to tweak the dome position?
My dome certainly isn’t new, but in pretty good condition, so would prefer to avoid major surgery.
I have a plan for the dome motor – it will probably need a couple of attempts to get it right, but a solution is possible. Finding the time is another. In the autumn perhaps when the gardening duties are slackening off is best bet.
I need to spend some quality time with a Raspberry Pi to and some NEMA 23 motors too.
EDIT: Someone kindly pointed out that the 315mm is a Planewave CDK and comparable in length with a C14. Very nice bit of kit, but a bit out of my budget range. 🙂