I would suspect the Autostar II controller - the symptom seems like a 'stuck' key that tells the telescope to slew in one direction. The controller can be opened with no problems - just be sure not to lose and parts by doing it inside. The keys are molded rubber that press to the curcuit board to make contact. Clean carefully with a dry lint-free cloth and re-assemble. Note: the red filter on the top end falls out when the case is opened, so make sure it is in place when closing. When testing, make sure the axis clamps are loose so the gears can free-wheel without causing damage. Also - do not leave batteries in the telescope in not being used - the last thing you need is a leak.