My experience is with the Classic Lx200...
Found a couple of links which may be of interest...
https://www.cloudynights.com/topic/3...0-mirror-lock/
https://astromart.com/reviews/telesc...e-lx200-14-sct
Hope you resolve the issue.
[Edit] I'm not suggesting at this stage you need to completely strip the Meade....just some ideas as to how the focuser works and may be rectified if needed.