Philips Bucky Diagnost

Looked at a Philips BuckyDiagnost system today along with a co-worker. The reported problem was that they couldn't make a tabletop shot without pulling out the table bucky tray first. When they pushed in the bucky tray, the system ready light went out and they couldn't make a shot. Looked in tray and found a marker that was stuck in the tray. Figuring that was the problem, we removed the marker and tested, everything seemed to work. We left and thirty minutes later got a call that it wasn't working again. Went back and troubleshot and found intermittent system ready light when in the tabletop mode. Took stoppers off end of table and slid table top off enough to get to bucky. Heard clicking in relay on circuit board as system light would go on and off by itself. When we pushed the test button on front of the control handle, it said cassette still in table bucky, but it was not. We suspect either the optical sensor that detects a cassette is malfunctioning, or the circuit board (or relay on board) is bad. Stay tuned...