Philips Intera-Achieva: intermittent scan aborts with fiber-link errors
What happened
As reported in the case, a couple of times a day an active scanning protocol stopped. The CDAS dump showed communication errors between CDAS and TXR, PFEI and the CfInt fiber interface, plus fiber fault flags. The PFEI and CDAS board tests passed normally, and the system had recently been relocated.
What was checked
- Review of the CDAS dump to see which links flagged errors and how the events relate to scans.
- Running the PFEI and CDAS test routines; both passed, pointing away from the digital boards themselves.
- Visual inspection of the fiber path and checking the fiber glow in a dark room to expose a weak or intermittent transmitter or a disturbed connection after the move.
Cause
The engineers found the fault in the external optical module of the CfInt fiber interface: the transmitter OSDH50M2 or the receiver OEDH50M2 was failing intermittently, most likely disturbed or degraded by the relocation. Passing board tests cover the logic only, not marginal optical power, so the link stayed alive in tests and dropped under real scanning.
What was done
Replacement of the faulty optical module restored stable communication and normal scanning in this case. The engineers also discussed, but did not apply, an idea of retrofitting the TXR1 and CfInt3 units with SFP-based transceivers and matching the logic levels, since the original modules are long out of production.
Safety
The MRI magnet field is always present even when the system is off, so use only non-ferromagnetic tools and keep loose parts controlled near the bore, and de-energise and verify the rack before opening it to swap optical modules.
Lesson: Intermittent link errors appearing right after a system move should be chased at the physical fiber layer first — board tests can pass while a marginal transmitter, receiver or disturbed connector drops out only under real scanning load.
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.