Opera T90: jerky column travel
What happened
The column of the X-ray unit moved in strong jerks during travel, and error 031 appeared periodically (reported in the case).
What was checked
- Inspected potentiometer 3pt4; the in-circuit voltage reading looked normal.
- Swapped the identical drivers 23S3 and 23S4 — no change in behaviour.
- Checked the second potentiometer and inspected the driver circuit, including resistor solder joints.
- Removed potentiometer 3pt4 and measured it on the bench; the engineers found the resistance jumping in steps, which the in-circuit voltage check had not revealed.
Cause
Faulty potentiometer 3pt4: its resistance changed in jumps. Reported in the case, the fault only showed when the potentiometer was measured after removal.
What was done
Replacement of potentiometer 3pt4; the jerking and error 031 did not return after the repair.
Safety
De-energise the system before measuring drive components, and before returning it to use confirm that the column stops at the limit switches and on emergency stop, then run the electrical safety test.
Lesson: A potentiometer can pass a quick in-circuit voltage check and still be faulty, so confirm it by measuring resistance on the removed part.
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.