Brilliance CT

• Faulty slipspring e-stop assembly
• Poor contact in the E-Stop ring/chain
• Blown fuses or wrong switch positions under the left-hand cover

1. Walk the whole e-stop chain, including the buttons under the front and right covers and the couch stopper limit switch
2. Check the fuses on the anode and cathode modules
3. Check the fuses and switch positions under the left cover
4. Check gantry tilt and confirm all CPM boards report ready
5. Restart from the blue button and from the transformer, then review the logs

Solved in one case by repairing/replacing the faulty slipspring e-stop. In a similar post-maintenance case the likely cause was a lost contact in the E-Stop ring, with the fuses and switches under the left cover as further suspects.

• DMC collimator A-plane parameters lost or corrupted
• Collimator filter cracked and detached from its mount (possibly damaged during transport or installation)
• Collimator mechanism sticking

1. Poll the circuit over CAN and check the e-stop circuit
2. Visually inspect the collimator filter and its mount
3. Review the density readings during calibrations
4. Make a fresh A-plane backup before any collimator work

Solved by loading the A-plane parameters from the calibration file into the DMC and restarting. A cracked filter was likely fixed by replacing the collimator/filter after taking a fresh A-plane backup. Engineers disagreed on whether lubricating a sticking mechanism helps: the effect is likely temporary, the Brilliance collimator is considered maintenance-free, and a full calibration is needed after any disassembly.

• Zero gate flag misaligned, so it does not coincide with the resolver northmark pulse
• Bent metal plate damaging or blocking the position-sensor optocoupler

1. Trace the signal in the logs and bug report
2. Ring out the wiring from the optocoupler to the DMC
3. Inspect the metal flag/plate for bending
4. Swapping the optocoupler board and the DMC did not help in the solved case, so check the flag alignment first

Solved by re-adjusting the zero gate flag position so it lines up with the resolver northmark. For a similar position-sensor error, the likely fix is to check or replace the optocoupler and correct the bent plate.

• Faulty spindle block (rotor drive)

1. Reflash the RHost and restore the host backup
2. Inspect the slip-ring contacts and brushes
3. Check the RHost seven-segment display
4. If the spindle block is replaced, the spindle block commissioning in Service Tools confirms the motor turns the right way

Solved by replacing the spindle block. Reflashing and restoring the backup did not help.

• Low mains voltage at the gantry that sags further during high-current, high-kV scans
• Mains supply voltage out of tolerance (too high)

1. Measure the supply voltage at the gantry at rest and during a high-load scan
2. Measure the incoming supply before the UPS and confirm your meter is reliable (one case questioned the meter battery)
3. Clean the slip ring and brushes

Solved by tracing the problem to low mains voltage (about 440 V at the gantry, sagging to about 410 V during scans). Replacing the HSS and the generator rectifier had not helped. In the overvoltage case the system was switched off to avoid damage until the supply was corrected.

• Software add-on not reinstalled after the system disk was replaced
• Worn HDDs in the RAID, possibly made worse by the power supply
• Motherboard degradation (suspected bad solder joints)

1. Review the reconstructor errors in the logs
2. Check the drivers and the ACQ board firmware
3. Check the RAID disk health and the reconstructor power supply
4. Check whether the motherboard responds to warming (this suggests solder faults)

Missing table: solved by installing the add-on. RAID: solved by replacing the HDDs with SSDs, which ran reliably for years; one suggestion was SSDs for the OS and programs, with the swap file and data on an HDD RAID. Motherboard: it started after warming, but this is a temporary sign only. Replacing the motherboard or server is the likely fix.

• Phantom calibration out of date
• Detector temperature not stable (detectors cooled by full shutdowns)
• Tube kV deviation or acculon density setting
• Transient Vicor power supply dip (for one-off artefacts)

1. Review the bad detector graphs and the date of the last phantom calibration
2. Check the actual tube kV over CAN
3. Measure the output with a dosimeter
4. Check the acculon density setting and let the temperature stabilise before retesting
5. For a one-off artefact, save the logs and take a BAG_REPORT straight away

These are likely fixes only: run a phantom calibration; adjust the acculon density, let the temperature stabilise and repeat the failed tests; for detector cell dropouts, use System Off on the console instead of a full power-off so the detectors stay warm; for a one-off artefact, a gantry reboot usually restores normal operation.

• Couch control board not resetting after a power or command glitch
• Couch control board or encoder fault

1. Watch the couch board indicators and review the logs
2. Check all supply voltages and the CAN bus connector
3. Check the encoders (blue unit)
4. Compare the calculated couch travel with the potentiometer feedback

Probable cause is the couch control board. The recommended steps were to reflash the CPM module on the board and check the supplies and the CAN connector. The case was not confirmed as solved.

• X-ray tube anode failure
• Rotor spin-up board or soft-start fault

1. Confirm supply voltage at the tube housing
2. Measure the stator winding resistance
3. Replace the fuses and retest
4. Check the spin-up board and that the soft start operates

Probable diagnosis was a failed tube anode. No repair was confirmed.