If it is truly an EC the 497 should work--

http://www.chriscamera.com/MeadeETX.htm

http://www.satobs.org/seesat/Mar-1999/0348.html

Do a RESET on the controller-- you will loose everything-- and have to retrain, re-calibrate-- etc---- Go to TELESCOPE and select the correct model "ETX"-- tell us what happens.