Problem(s) Encountered:

From ~2am, telescope pointing had become completely wrong.

When I moved the telescope to zenith, the Dec. difference is about 20 degree.  So, I manually moved the telescope near zenith, and then initialized position using ''zero'' command.

However, the pointing error was still so large that I couldn''t find any nearby bright stars and our targets in CCD field.

Solutions:

Came in to find the telescope pointed a fair ways south of zenith.  Physical and stated positioning was certainly different.  Brought telescope to zenith via tilt sensor display (-003/-008) and zeroed the telescope using the following command:

zero ra=xx:yy:zz (local sidereal time plus a few seconds) dec=31:57:12 equinox=2016.9

then hit <enter> when the sidereal time matched the entered ra time.  Command took without issue.  Slewed telescope to a couple points on the sky and then returned it to zenith.  All motions appeared to work as commanded.