Siemens Magnetom Multiva 1.5T: patient table creeps out and will not release
What happened
The patient table crept out slowly and would not release; the fault was intermittent and sometimes settled temporarily while the control joystick was being operated.
What was checked
- System self-tests ran clean, so the fault was chased as an intermittent one.
- The microswitches in the table drive were suspected first and were checked.
- Since the behaviour followed the joystick, attention moved to the joystick itself and its optocoupler was inspected.
Cause
The engineers found a faulty optocoupler inside the control joystick: its drifting output was misread by the table control as movement and release commands, which matches the creeping table and the floating error pattern reported in the case.
What was done
The faulty optocoupler in the joystick was replaced. After the replacement the table moved and released normally and the fault did not return — the case was reported as solved.
Safety
Before any work on the table or joystick, take the patient off the table and secure it against unexpected movement, use only non-magnetic tools inside the magnet room, and function-test the stop and release controls before returning the table to use.
Lesson: When an intermittent table fault reacts to handling the controller, check the controller's own electronics before dismantling the actuator.
Covered in the course: MRI Service — Level 2: Fault-Finding →
Written from an anonymised case shared by service engineers. It is not a manufacturer instruction and grants no authorisation. Independent note; names are trademarks of their owners.