Philips Achieva 1.5: intermittent optical link error to the CDAS rack
What happened
Recurring error on the optical communication channel involving the CDAS acquisition rack. Swapping the CFint board helped for a single scan, then the error returned. As reported in the case, the fault appeared or cleared when a person walked up to the rack or when the front cabinet door was opened.
What was checked
- Replaced the CFint board in the CDAS rack — helped only once, the error came back
- Checked the power module in the filter box and its cooling fan
- Inspected the fiber-optic cable run for tight bends and kinks
- Checked the optical transceivers in the TXR unit
- Tested whether external or ambient light affected the optical link
Cause
Probable cause in this case: degradation somewhere in the optical path — connectors, transceivers or the fiber itself — leaving the link with little margin and, possibly, letting external light reach the receiver through a poor connection, which would explain the sensitivity to a person near the rack or a moving door. Not yet finally confirmed; the engineers expect the planned parts replacement to settle it.
The cause is probable and was not fully confirmed.
What was done
Optical modules and related boards were ordered, and the replacement is scheduled. For now the system runs stably, but the engineers treat this as temporary until the optics are swapped and the link holds under load.
Safety
The MRI magnet field is always on, so keep ferromagnetic tools and loose metal parts away from the magnet room while tracing this fault, and complete the manufacturer's electrical safety checks before returning the system to clinical use.
Lesson: When a fault follows a person's presence or a door opening, suspect the physical layer first — light leakage and marginal contacts are far more common than a dead board, and a single successful run after a swap proves nothing.
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.