On this page
Asset Type
Manufacturer
Model
What This Guide Helps With
This guide helps troubleshoot a Philips HeartStart MRx displaying the startup error Critical Failure Detected. Service unit. The error may prevent reliable defibrillation, monitoring, pacing, or clinical readiness and should be treated as a patient safety issue until the device is verified safe for use.
Step-by-Step Troubleshooting
Ensure Patient Safety First
- Remove the HeartStart MRx from clinical use immediately if the error appears during startup, patient care, transport, or readiness checks.
- Provide clinical staff with a known-good defibrillator before continuing troubleshooting.
- Do not leave the device available for emergency response while the critical failure message is active.
- Expected outcome: Patient care is supported by a reliable backup defibrillator.
Verify the Reported Error and Behavior
- Power the unit on and confirm the exact displayed message: Critical Failure Detected. Service unit.
- Observe whether the error appears during startup, self-test, after battery installation, after AC power connection, intermittently during use, or after a drop, cleaning, battery change, or storage.
- Check whether the device reaches normal operating screens or remains locked in the failure condition.
- Expected outcome: The critical failure message is confirmed and its timing is documented.
Remove the Device From Service if the Error Is Active
- If the error remains present, do not leave the MRx available for patient use.
- Attach an Out of Service label and notify the clinical area that the unit is not available.
- Expected outcome: The device is clearly identified as unavailable.
Check External Power First
- Connect the MRx to a known-good AC outlet using the proper power cord.
- Confirm the power cord is fully seated at the wall outlet and the device.
- Check for cord damage, loose plug fit, bent pins, damaged strain relief, or poor outlet connection.
- Expected outcome: The unit receives stable external power.
Check Battery Condition and Seating
- Remove and reseat the batteries.
- Inspect the battery contacts and battery wells for debris, corrosion, damage, or fluid contamination.
- If available, test with known-good charged MRx-compatible batteries.
- Expected outcome: The unit powers with known-good batteries and no obvious battery connection issue is present.
Check the Ready For Use Indicator
- Observe the Ready For Use indicator before and after powering the device on.
- Look for ready status, a red X or service indication, no indicator activity, intermittent status change, or changes after battery or AC power is connected.
- Expected outcome: The readiness status is compared against the reported startup failure.
Inspect the Unit for External Damage
- Check the case, display, therapy connector area, paddles or pads connector, ECG connector, printer door, battery wells, and power input area.
- Look for cracked housing, liquid intrusion, damaged connectors, bent pins, loose modules, evidence of a drop, burning smell, heat, or abnormal noise.
- Expected outcome: No external damage or contamination is found, or damage is identified and documented.
Disconnect Accessories and Recheck Startup
- Remove nonessential accessories from the device, including ECG cable, SpO₂ cable, NBP hose if equipped, therapy cable, pads, paddles, and data cards if applicable.
- Power the device on with only required power connected.
- Expected outcome: The unit either starts normally without accessories or the critical failure remains.
Reconnect Accessories One at a Time
- If the error clears after accessories are removed, reconnect one accessory at a time.
- Restart the device after each connection if needed to confirm whether the error returns.
- Check whether a specific cable, sensor, therapy cable, or module causes the failure to return.
- Expected outcome: A faulty accessory is isolated, or no accessory changes the failure.
Run an Operational Check if the Unit Can Power On
- If the MRx powers on far enough to allow testing, perform an Operational Check according to facility procedure.
- Do not perform patient-use testing while the device is connected to a patient.
- Expected outcome: The Operational Check either passes or reports a specific failure.
Review Available Status Information
- If accessible, review the Status Log in Service Mode or through the facility’s approved service process.
- Document repeated failure messages, timestamps, test failures, or readiness status changes.
- Expected outcome: The log supports whether the error is isolated, intermittent, or recurring.
Determine Whether the Issue Was External or Device-Related
- If the error clears after correcting power, battery seating, or a faulty accessory, repeat startup and readiness checks.
- Verify the Ready For Use indicator returns to normal.
- Run an Operational Check if available and required by facility policy.
- Expected outcome: The unit passes checks and no longer displays the critical failure message.
Stop When Resolved
- If the error clears, the Operational Check passes, and the Ready For Use indicator is normal, return the device to service according to facility policy.
- Document the issue, cause, corrective action, and final status in the work order.
- Expected outcome: The device is safely returned to clinical availability.
If the Problem Persists
If the Critical Failure Detected. Service unit. message remains after checking AC power, batteries, accessory connections, physical condition, Ready For Use status, and available operational checks, external causes have been ruled out.
A persistent critical failure strongly indicates an internal device fault or service-level failure condition.
Remove the device from service, label it Out of Service, and send it for repair or bench evaluation.
Do not return the HeartStart MRx to clinical use with an unresolved critical failure message.
Clinical Use Tip
Never troubleshoot a defibrillator with an active critical failure while it is assigned to emergency response or patient care. Move the patient or clinical area to a backup device first, then evaluate the failed HeartStart MRx away from active patient use.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
"Philips HeartStart MRx displays Critical Failure Detected. Service unit. during startup. Device not considered ready for patient use."
Cause
What was observed during troubleshooting.
Example:
"Checked AC power, batteries, Ready For Use indicator, external condition, and accessories. Error remained present, indicating likely internal service-level failure."
Resolution
What action was taken.
Example:
"Removed device from clinical use, labeled Out of Service, documented failure behavior, and escalated for service/bench evaluation."
Helpful Details to Include (If Known)
- Alarm behavior
- Accessories swapped
- Power behavior
- Environmental factors
- Indicator lights
- Final device status
Final Thought
A critical failure message on a defibrillator should always be treated as a patient safety issue first. Start with simple power, battery, accessory, and readiness checks, but do not force a return to service if the error remains. Proper escalation and clear CCR documentation protect both patients and clinical staff.
That is successful troubleshooting.