Before attempting any repairs, ensure you:
This was the "ghost." The elevator wasn't lost; it just didn't know where the ground was. He followed the manual's calibration procedure for the tape selector system. Up in the hoistway, perched on top of the car, he cleaned the magnetic sensors with a lint-free cloth, exactly as prescribed on page 88. One speck of dust could blind the system to its own location. Chapter 3: The Door Symphony Schindler 330a Elevator Repair Manual