Siemens Magnetom Essenza: patient table will not drive, false 'patient moved' message
What happened
After the patient was fed into the bore, the table refused to move under program control and reported that the patient had moved. Restarting the table did not help.
What was checked
- Power restart of the table — the fault returned at once.
- Table cranked out manually with the hand crank (brake released) to confirm free mechanical travel.
- Belt tension checked and the belt removed — no binding or mechanical fault found.
- Horizontal drive motor and its wiring replaced — no change in behaviour.
- Movement tested axis by axis from the console: the horizontal drive failed first, and after it was sorted the vertical drive failed as well.
Cause
In this case the engineers found two drive boards failing in sequence: first the horizontal movement board, and then, after it was replaced, the vertical movement board. The 'patient moved' message was a false flag from the bad boards, not real patient motion.
What was done
The horizontal drive board was replaced; when the vertical drive then failed, that board was replaced too. After both board swaps the table moved normally under program control, and the case was closed as solved.
Safety
Before opening the drive units, isolate the table supply and secure the table against rolling — with the brake released it can move freely — and carry out the electrical safety test before returning the table to patient use.
Lesson: A motion warning that blames the patient can originate in the drive electronics itself, so test the drive boards one by one before chasing motors, belts and mechanics.
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.