Achieva

• A faulty optical transmitter (OSDH50M2) or receiver (OEDH50M2) module on the CfInt
• Ageing or sharply bent fiber-optic cable, especially after the system has been moved
• A faulty transceiver on the TXR side
• Outside light getting into the optical connections

1. Read the CDAS dump at the time of the error and note which link is reported (cdas-txr, pfei-cfint, fiber)
2. Run the PFEI and CDAS tests. Passing tests do not rule out an intermittent optical fault.
3. Check the fiber routing for tight bends. In a dark room, check whether the fiber lights up properly.
4. Check the transceivers in the TXR
5. See whether room or cabinet lighting, or opening the cabinet door, changes the behaviour
6. Check the filter-box module and its fan

In the solved case, replacing the faulty optical module on the CfInt fixed the fault. In another case a new CfInt board fixed it for only one exam. Replacement boards and optics were then ordered, so if a new CfInt does not cure it, the optical modules and fiber are the likely cause. Run the manufacturer's checkout after any replacement.

• Broken wires in the table cable where it bends. In the solved case, 2 of 22 wires were broken.
• A damaged or cracked motor cable to the table drive
• Limit switches on the bridge sticking
• Oxidised auxiliary contacts on the contactor near the solid-state relays, at the bottom of the table
• A broken cable running to the top of the table, to the encoder and switches
• A faulty servo amplifier

1. Do a full reboot and check the fuses under the table
2. Try manual mode, and check whether vertical movement still works
3. Check the logs for PLC/servo errors
4. Check the continuity of each wire in the table cable, especially at bend points
5. Check the motor cable and the wiring to the limit switches inside the table
6. Inspect the limit switches on the bridge for sticking
7. Take apart and clean the auxiliary contactor contacts if they are oxidised

Solved case: the broken wires in the table cable were repaired. Reterminating the cable so the bend point moves is recommended. For the servo-OK error, a damaged motor cable is the likely cause, so check it and replace it if needed. For the intermittently hanging table no confirmed fix was recorded; check the switches, contacts and cable listed above. Run the manufacturer's checkout of table movement afterwards.

• The fill hatch on the magnet module not seating properly

1. Re-seat the interface cables, coax cables and ribbon cables in the gradient cabinet, and the axis connections
2. Inspect the hatch on the magnet module for a proper fit
3. Next steps that were planned: check the capacitors in the cabinet and the connections from the cabinet to the coil, and run a spike test

Solved: the eddy current test passed once the hatch was made to seat properly. Leave anything on the magnet's cryogenic side that is more than closing a cover to the manufacturer.

• Problems in the gradient amplifier cooling circuit: low flow in the secondary circuits or low coolant level in the tanks
• Thermal breakdown of the PDM module after the fan facing it failed or the air filter clogged (likely)

1. Review the detailed logs at the moment of the error
2. Check the cooling cabinet and heat exchanger in the gradient amplifier cooling circuit
3. Watch the amplifiers when the error occurs
4. Check flow in the secondary circuits and the coolant level in the tanks
5. Check that the fan facing the PDM module works and that the filter is not clogged

No confirmed fix was recorded. Overheating from poor cooling (flow, coolant, fan or filter) is the likely cause, so fix the cooling first, then replace any damaged module and run the manufacturer's checkout.

• A shorted diode in the MCD 162-12io1 module. This was likely caused by overcurrent during input voltage dips, when the thyristor is open on the rising edge and the storage capacitor has been drained by the inverter.

1. Check the MCD 162-12io1 module
2. Review how the soft-start circuit behaves
3. Assess the mains supply for voltage dips

No confirmed fix was recorded. The likely cause is a failed diode in the MCD 162-12io1, so replace the module and look into input voltage dips as the root cause. Run the manufacturer's checkout afterwards.

• A broken power wire to the coil preamplifier. Preamplifier power is carried over the coax cable.

1. Rule out metal on or in the patient
2. Run the PFEI and CDAS tests. They passed in this case, so they do not rule out a coil fault.
3. Check the continuity of the preamplifier power path through the coil cable

The likely cause is a broken preamplifier power wire in the head coil. Repair or replace it, then verify with the coil test.

• A failed capacitor in the power supply at the bottom of the table (the outermost one), for the lighting failure (likely)
• Interference from a faulty tunnel lamp whose broken filament made intermittent contact (suspected source of the ripple)
• Poor contact of the PCI boards in the reconstructor
• Poor coil connector contacts, for example after improper cleaning

1. Check the fuse under the table cover
2. Check the tunnel lamps and their holders
3. Check the outermost capacitor in the table power supply
4. For artifacts: compare against the built-in Q-body coil and other anatomies to isolate the head coil
5. Clean and degrease the coil connector pins
6. Re-seat the PCI boards in the reconstructor

No fix here is confirmed. For dead lighting, replacing the outermost power supply capacitor at the bottom of the table is the likely fix. In the artifact case, replacing the tunnel lamps and re-seating the reconstructor PCI boards cleared the artifacts for 4 days of observation. The root cause was not confirmed, so keep monitoring and keep the head coil under suspicion.

• Wrong jumper settings on X20–X23. These jumpers set the board's identity (first or second board) in an 8/16-channel system.

1. Compare the X20–X23 jumper settings on the new board with the old board

Setting the jumpers to match the old board likely fixes it. In the field case the jumper was moved from X20 to X21. Rerun the tests afterwards.

• A failed SAS hard disk in the reconstructor
• A failed RAID array, with the system running on its backup array (suspected for slow PACS transfers)
• Poor communication between the reconstructor and the host

1. Confirm the disk has failed and replace it
2. Reboot after replacing it and check whether network boot is enabled
3. For slow PACS transfers: check the RAID array's status and the reconstructor-to-host link

For the disk failure: replace the disk. After a full failure the reconstructor software is said to reinstall itself from the host; after a partial failure network boot may be needed (probable). For slow PACS transfers no fix was recorded; check the RAID and the reconstructor-to-host link first.