Siemens Axiom Luminos dRF: intermittent fault during table tilt blocking movement
What happened
Reported in the case: during table rotation/tilt the system intermittently drops into a fault (1102/17) that blocks all movement and clears only after a reboot; at the same tilt angle the error appears and disappears.
What was checked
- Checked both tilt potentiometers on the axis — readings were plausible.
- Confirmed the fault meaning: the position difference between encoder and potentiometer is too large.
- Ran the tilt axis through the reference mark in the manufacturer's service software.
- Repeated the home position adjustment.
- Inspected potentiometer and encoder wiring for noise, and checked grounding.
- Clarified the axis layout: the engineers found two potentiometers per axis and identified the one fed with 10 V (reported in the case) as the suspect.
Cause
No confirmed cause in the case; the intermittent encoder-versus-potentiometer disagreement at a fixed angle pointed to a worn or drifting powered tilt potentiometer rather than the encoder, wiring or grounding.
The cause is probable and was not fully confirmed.
What was done
The engineers recommended replacing the potentiometer fed with 10 V (reported in the case), followed by linearity adjustment and a new home position calibration as a procedure from the manufacturer's service documentation; the outcome was probable at the time of the case, not yet confirmed.
Safety
Before working on the tilt axis, mechanically secure the table against unintended movement — a tilted table stores significant gravitational energy — and complete the electrical safety checks, including protective earth, before returning the unit to clinical use.
Lesson: When a position-mismatch error comes and goes at the same angle, suspect the powered feedback potentiometer for wear or drift first, and always recalibrate the axis after replacing any position sensor.
Covered in the course: X-ray 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.