ZOLL R Series

Asset Type

Defibrillator

Manufacturer

ZOLL

Model

R Series

What This Guide Helps With

This guide helps troubleshoot DEFIB FAULT 79 on a ZOLL R Series defibrillator. This fault appears during POST and indicates a defib/pace self-test failure that may prevent reliable therapy delivery.

Because this fault is tied to defibrillation and pacing readiness, the device should not be trusted for patient care until the problem is verified, corrected, and the unit passes required operational checks.

Step-by-Step Troubleshooting

Ensure Patient Safety First

• Immediately remove the defibrillator from patient use if DEFIB FAULT 79 is displayed.
• Do not use the device for defibrillation, synchronized cardioversion, pacing, or patient monitoring if therapy functions are affected.
• Replace it with a known-good defibrillator.
• Notify clinical staff that the unit is not available for patient care.

Expected outcome: Patient care is moved to a functional defibrillator.

Why it matters: A defibrillator showing a POST therapy fault cannot be trusted for emergency use.

Verify the Reported Error and Behavior

• Power the unit on and observe startup behavior.
• Confirm that DEFIB FAULT 79 appears during POST.
• Note whether the error appears immediately, intermittently, or after a readiness or self-test.
• Check whether the unit also shows therapy-related symptoms such as failed charge, pacing failure, or defib test failure.

Expected outcome: DEFIB FAULT 79 is reproducible or clearly observed.

Why it matters: This confirms a true system-reported POST failure rather than a user report, old log entry, or unrelated readiness issue.

Check AC Power and Battery Condition

• Connect the R Series to a known-good AC outlet.
• Confirm the AC power indicator is present.
• Check battery condition and charge status.
• Swap in a known-good compatible battery if available.
• Restart the unit and observe whether the fault returns.

Expected outcome: Unit powers normally without low-power behavior.

Why it matters: Weak batteries, poor charging, or unstable power can create startup problems, although DEFIB FAULT 79 usually points deeper than basic power.

If this resolves the issue, document the defective battery or power issue and return the unit to service only after completing required operational checks.

Inspect Therapy Cables, Pads, and External Accessories

• Inspect defib and pacing cable connections.
• Check therapy cable pins, connectors, and strain relief.
• Remove damaged or contaminated cables from use.
• Test with known-good pads or a known-good therapy cable if available.
• Confirm no accessories are loose, wet, damaged, or incompatible.

Expected outcome: Accessories are clean, intact, and properly connected.

Why it matters: Therapy cable or pad issues can mimic defib and pacing problems and should be ruled out before condemning the device.

If a cable or accessory resolves the issue, replace the failed accessory and complete required defib and pacing verification before returning the unit to service.

Perform a Basic Physical Inspection

• Inspect the unit for cracks, drops, impact damage, fluid intrusion, corrosion, or contamination.
• Check the therapy port and external connectors.
• Listen for abnormal sounds during startup.
• Check for burnt odor or signs of overheated electronics.
• Confirm the device is clean and dry.

Expected outcome: No external damage or contamination is found.

Why it matters: Physical damage or fluid intrusion can cause internal therapy module faults and makes continued use unsafe.

Attempt a Controlled Restart

• Power the unit off.
• Disconnect from AC power briefly.
• Remove and reseat the battery.
• Reconnect AC power.
• Power the unit back on and observe POST.

Expected outcome: The unit completes POST without DEFIB FAULT 79.

Why it matters: A temporary startup fault may clear after a proper power cycle, but repeated DEFIB FAULT 79 should be treated as a real failure.

If the fault clears, complete the required operational verification before returning the unit to service.

Run the Appropriate Readiness or Operational Check

• Follow your facility’s approved ZOLL R Series checkout process.
• Confirm the device can complete its readiness or self-test process.
• Verify that no defib, pacing, or charge-related faults return.
• Record any failed test result.

Expected outcome: The device passes required checks with no recurring fault.

Why it matters: DEFIB FAULT 79 is related to a defib/pace POST failure, so the unit should not be returned to service based only on the screen clearing once.

Determine Whether the Issue Is Accessory-Related or Device-Related

• Likely accessory-related: The fault clears after replacing a therapy cable, pads, or external accessory, and the unit passes POST and operational checks afterward.
• Likely device-related: DEFIB FAULT 79 returns with known-good accessories, appears during POST before clinical use, or the unit fails readiness, defib, or pacing checks.
• Also treat the issue as device-related if there are signs of internal failure, damage, heat, odor, or fluid intrusion.

Expected outcome: The issue is narrowed to either an external accessory problem or an internal defib/pace subsystem failure.

If the Problem Persists

If DEFIB FAULT 79 persists after checking power, battery, accessories, therapy cables, and basic physical condition, external and common causes have been ruled out.

A persistent DEFIB FAULT 79 strongly indicates an internal PD module defib/pace failure during POST. The service-level corrective action is typically replacement of the PD engine.

• Remove the defibrillator from service.
• Label it Out of Service.
• Do not return it to clinical use.
• Send it for repair, bench evaluation, or vendor/service-level support.
• Document that the fault persisted with basic external causes ruled out.

Knowing when to stop is proper troubleshooting. A defibrillator with a persistent POST therapy fault should not be trusted for patient care.

Clinical Use Tip

Never troubleshoot DEFIB FAULT 79 on an active patient. Move the patient to a backup defibrillator first if monitoring, defibrillation, cardioversion, or pacing may be needed.

A defibrillator with an unresolved POST therapy fault should be considered unavailable for emergency response.

Work Order Documentation (CCR Method)

CCR = Complaint, Cause, Resolution

Complaint

What was reported by the clinical staff.

Example:
"ZOLL R Series defibrillator displays DEFIB FAULT 79 during power-on POST. Unit fails startup readiness check and may not be reliable for defib or pacing use."

Cause

What was observed during troubleshooting.

Example:
"DEFIB FAULT 79 confirmed during POST. AC power, battery, external therapy cable, pads, and visible external condition checked. Fault persisted with basic external causes ruled out, indicating likely internal PD module defib/pace failure."

Resolution

What action was taken.

Example:
"Removed defibrillator from service and labeled Out of Service. Sent for repair/bench evaluation due to persistent DEFIB FAULT 79. Service-level action may require PD engine replacement."

Helpful Details to Include (If Known)

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

Final Thought

DEFIB FAULT 79 should be treated as a serious therapy-related POST failure. Start with patient safety, verify the exact fault, rule out external power and accessory problems, then escalate when the error persists. For a defibrillator, proper escalation is not overreacting; it is protecting the patient and the clinical team. Clear CCR documentation helps show what was checked, what failed, and why the unit was removed from service.

That is successful troubleshooting.