GE Healthcare OEC 9900 Series

Asset Type

C-Arm

Manufacturer

GE Healthcare

Model

OEC 9900 Series

What This Guide Helps With

This guide helps troubleshoot the COLLIMATOR STUCK error on the GE Healthcare OEC 9900 Series C-Arm. This condition means the collimator iris cannot properly open or close, making iris adjustment unavailable or unreliable. Because collimation affects beam limitation, image quality, and patient dose control, the device should not remain in clinical use if the field size cannot be controlled safely.

Step-by-Step Troubleshooting

Ensure Patient Safety First

• Remove the C-Arm from patient use if the collimator cannot be adjusted during a procedure.
• Stop using the unit if the radiation field cannot be properly controlled.
• Provide another C-Arm if collimation is needed for patient positioning, dose control, or image quality.
• Do not continue imaging if the field size cannot be verified or adjusted safely.

Verify the Reported Error and Behavior

• Power on the OEC 9900 Series and confirm the displayed message reads: Error: COLLIMATOR STUCK.
• Check whether the error appears at startup, during iris adjustment, intermittently during use, or after transport.
• Attempt normal collimator iris adjustment from the C-Arm controls.
• Observe whether the iris does not move, moves partially, moves slowly, makes abnormal noise, or returns the error after clearing.

Check for Obvious External or Physical Causes

• With the unit removed from clinical use, visually inspect the collimator opening area.
• Look for debris, tape, drapes, contrast residue, cleaning residue, physical damage, or signs of impact near the collimator housing.
• Do not force the iris blades or attempt internal disassembly.
• If a visible external obstruction is found, remove it only if it can be done safely without disturbing internal components.

Check C-Arm Control Inputs

• Operate the collimator iris controls from the C-Arm control panel.
• Verify that other nearby control functions respond normally.
• Look for stuck, damaged, or non-responsive control buttons.
• Confirm whether the issue is isolated to iris movement or part of a broader control panel problem.

Power Cycle and Recheck

• Power the system down using the normal shutdown process.
• Wait briefly, then power the system back on.
• Observe whether the error appears during startup or only when iris movement is commanded.
• Attempt iris adjustment again after restart.
• If the error clears, perform a functional check of collimator movement before returning the device to service.

Inspect Accessible Cables and Connections

• Inspect visible cable routing around the C-Arm head and collimator area.
• Look for loose connectors, pinched wiring, damaged insulation, strain from movement, or evidence of recent impact.
• If facility procedure allows, reseat accessible connectors related to the collimator control path.
• Do not open sealed assemblies or perform internal disassembly unless qualified and approved by your facility procedure.

Check for Mechanical Binding Symptoms

• Listen during attempted iris adjustment.
• Note whether the motor clicks, hums, grinds, stalls, or sounds like it is trying to move.
• Observe whether the iris moves partially and then stops.
• Do not manually force the collimator mechanism.

Consider Iris Motor or Drive Failure

• If the motor is silent during open and close commands, suspect a motor drive, wiring, control command, or power path issue.
• If the motor runs but the iris does not move, suspect a failed motor coupling, jammed mechanism, or mechanical binding.
• If movement fails in both directions, suspect motor power, motor wiring, motor drive circuitry, or a seized motor.
• Remove the device from service if motor or drive failure is suspected.

Consider Position-Feedback Problems

• If the iris appears to move but the error remains, suspect that position feedback is not changing correctly.
• Look for movement that stops unexpectedly, inconsistent iris position after restart, or repeated errors after partial movement.
• Document whether the iris physically moves when the system still reports it as stuck.
• Escalate for service evaluation of the collimator feedback path if the fault persists.

If the Problem Persists

If the COLLIMATOR STUCK error remains after checking for external obstruction, control input issues, restart behavior, visible cable problems, mechanical binding symptoms, and obvious damage, remove the C-Arm from service.

At that point, external causes have been ruled out and the issue may involve a failed iris motor, mechanical binding inside the collimator assembly, loose or damaged internal wiring, faulty collimator control circuitry, or position-feedback failure.

• Remove the device from service.
• Label it Out of Service.
• Send it for repair or bench evaluation.
• Escalate to qualified imaging service support if internal collimator service is required.

Clinical Use Tip

Never troubleshoot collimator movement on an active patient. Move the patient or procedure to a backup C-Arm first if beam limitation cannot be confirmed. A stuck collimator can affect radiation field control, image quality, dose management, and procedural workflow.

Work Order Documentation (CCR Method)

CCR = Complaint, Cause, Resolution

Complaint

What was reported by the clinical staff.

Example:
"User reported GE Healthcare OEC 9900 Series C-Arm displayed COLLIMATOR STUCK and the collimator iris would not open or close during adjustment."

Cause

What was observed during troubleshooting.

Example:
"Verified COLLIMATOR STUCK error during iris adjustment. No external obstruction or visible damage found. Error persisted after restart, indicating likely collimator iris motor, mechanical binding, wiring, control circuit, or position-feedback issue."

Resolution

What action was taken.

Example:
"Removed C-Arm from service and labeled Out of Service. Escalated for imaging service repair or bench evaluation of the collimator iris motor, wiring, control circuitry, and position-feedback components."

Helpful Details to Include (If Known)

• Alarm behavior
• Accessories swapped
• Power behavior
• Environmental factors
• Indicator lights
• Final device status

Final Thought

The COLLIMATOR STUCK error should be treated as a beam-limiting and patient safety concern. Start with simple external checks, confirm the exact behavior, avoid forcing the collimator mechanism, and escalate when mechanical or internal control failure is likely. Clear documentation helps repair teams focus on the iris motor, mechanical movement, wiring, control circuitry, and feedback path.

That is successful troubleshooting.