Siemens Symphony 1.5T: patient table fuse blows during horizontal travel
What happened
On a Siemens Symphony 1.5T, the F11 fuse (0.8 A as reported in the case) on the A5132 power board in the patient table base (PTAB) kept blowing every time the table moved horizontally.
What was checked
- The engineers rang out the switches cable for continuity and for shorts to the magnet frame/ground.
- They checked the table power supply circuit, then traced the wiring in the horizontal cable track while moving the table to reproduce the fault — the short appeared only in a specific table position.
Cause
The engineers found that conductors inside the horizontal cable track (drag chain) of the table were broken, and in a certain table position the damaged wires shorted to the shield, overloading the supply and blowing F11.
What was done
The damaged wiring in the horizontal cable track was repaired/replaced and the fuse was renewed; the table then moved without blowing F11 and the case was solved.
Safety
Treat a repeatedly blowing fuse as an active short: de-energise the table drive before opening the cable track, fit only the fuse rating specified in the manufacturer's documentation, and repeat the earth-continuity and insulation checks before returning the patient table to service.
Lesson: A fuse that blows only at one position of a moving axis points to chafed or broken wiring in the cable track, so ring out the moving harness at the fault position before suspecting the drive board.
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.