Academy / Field fault notes / Рентгенпром Програф
Рентгенпром · Програф
Rentgenprom Prograph: table drifts in height on its own
What happened
In the reported case, the vertical lift of the table/cassette carrier changed height by itself — the carriage drifted up and down with no command given.
What was checked
- The engineers checked the lift control buttons first — no stuck buttons or spurious commands were found.
- They went through the feedback chain: the resistor on the gearbox and the height potentiometer; replacing the potentiometer changed nothing.
- Only disassembly of the potentiometer unit showed the fault: the cotter pin had free play in the hole of the potentiometer shaft, so the position feedback signal wobbled.
Cause
Mechanical play in the height feedback path: the cotter pin fixing the potentiometer shaft had free travel in its hole, so the control system kept receiving a jittery position signal and
What was done
Safety
Lesson:
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.