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What This Guide Helps With
Troubleshooting a LIFEPAK 35 that will not power on, stalls during startup, shuts down, or fails to reach normal operation.
Step-by-Step Troubleshooting
Ensure Patient Safety First
Immediately provide clinical staff with another verified defibrillator if the LIFEPAK 35 fails to start or cannot complete normal startup.
Do not troubleshoot an unreliable defibrillator while it is connected to or supporting an active patient.
Expected: Patient care continues with a known-good defibrillator.
Why it matters: A startup failure makes therapy and monitoring availability uncertain and must be treated as a readiness issue.
Verify the Exact Startup Behavior
Attempt startup in a controlled Clinical Engineering environment and document exactly what occurs:
- No display or indicator response
- Brief power response followed by shutdown
- Device stalls at a startup screen
- Repeated restart or boot cycle
- Audible tones without normal display operation
- Error or service message
- Startup succeeds only on battery power
- Startup succeeds only with the AC Power Adapter connected
Expected: The failure pattern is repeatable and clearly documented.
If the device starts normally and the reported issue cannot be reproduced, continue with controlled operational verification before considering return to service.
Inspect for External Damage or Environmental Causes
Inspect the device exterior for:
- Impact or drop damage
- Liquid intrusion or contamination
- Damaged battery compartments
- Bent, recessed, contaminated, or damaged contacts
- Damaged external power connections
- Unusual heat
- Burning odor
- Evidence of recent cleaning-fluid intrusion
If unusual heat, odor, liquid intrusion, or significant physical damage is found, stop troubleshooting.
Expected: No external safety condition explains the startup failure.
If abnormal conditions are present: Remove from service and escalate for repair evaluation.
Verify Battery Installation and Seating
Remove and reinstall the installed LIFEPAK FLEX battery or batteries, confirming each battery is fully seated and mechanically secure.
Inspect accessible battery and device contacts without disassembling the unit. Look for:
- Contamination
- Bent or damaged contacts
- Foreign material
- Physical battery damage
- Swelling or abnormal heat
The LIFEPAK 35 uses Stryker LIFEPAK FLEX lithium-ion battery power options.
Expected: Batteries are correctly installed with clean, undamaged accessible contacts.
If reseating resolves the startup issue, perform full operational verification before returning the device to service, then stop.
Check Battery State With Known-Good Components
Substitute a charged, compatible, known-good LIFEPAK FLEX battery when available.
Do not assume a battery is functional solely because it was recently charged or displays an apparent charge indication.
Test methodically:
- Attempt startup with the original battery configuration.
- Substitute a verified known-good battery.
- Repeat the startup attempt.
- Compare behavior.
Expected: The device starts consistently with known-good battery power.
If the known-good battery resolves the issue: Remove the suspect battery from service for separate evaluation and complete operational testing of the LIFEPAK 35 before return to use.
Verify the External AC Power Path
When equipped with the LIFEPAK 35 AC Power Adapter:
- Confirm the wall outlet is functional using an approved test method.
- Confirm the AC cord is fully seated.
- Inspect the cord and adapter for damage.
- Confirm the adapter connection to the device is secure.
- Observe the device’s external/auxiliary power indication.
Stryker states that the LIFEPAK 35 AC Power Adapter can operate the monitor/defibrillator with or without batteries installed and can charge installed batteries.
Stryker’s current Performance Inspection Procedure also identifies illumination of the Auxiliary Power indicator when the device is connected to the Power Adapter and an AC source.
Expected: External power is recognized and the device starts normally.
If operation is restored by correcting the outlet, cord, adapter seating, or external connection, perform complete operational verification and stop.
Isolate Battery Power From External Power
Compare startup behavior under controlled conditions:
- Known-good battery power
- Approved AC Power Adapter power
- AC power with installed batteries, as applicable
Document whether the device:
- Fails on all power sources
- Starts only on AC power
- Starts only on battery power
- Shuts down when one source is removed
- Shows inconsistent power recognition
Expected: Startup behavior helps separate an external power-source problem from a likely device-level fault.
Why it matters: A device that starts from one verified source but not another should not immediately be classified as having a generalized internal startup failure.
Disconnect Nonessential External Accessories
With the device removed from clinical use, disconnect nonessential external accessories that are not required for basic startup, such as applicable:
- USB accessories
- External communications connections
- Auxiliary accessory cables
- Monitoring cables
- Other removable peripherals
Leave only the minimum configuration needed for a controlled startup test.
Expected: The device reaches normal operation without an external accessory influencing startup.
If removing a specific accessory resolves the issue, inspect and evaluate that accessory separately. Do not return the complete system to use until the affected configuration has been verified.
Perform a Controlled Power Reset
With the device off and removed from patient use:
- Disconnect the external AC Power Adapter.
- Remove the removable battery power sources.
- Inspect and reseat only after confirming no damage or abnormal condition is present.
- Reinstall a verified known-good battery.
- Attempt a fresh startup.
- Repeat using verified external power if necessary.
Do not repeatedly cycle an unstable device in an attempt to force it into operation.
Expected: The LIFEPAK 35 completes a stable startup and remains operational.
If the reset resolves the symptom, continue with complete performance verification before return to service.
Review Displayed Errors and Available Service Information
If the device powers far enough to display a message, record the exact wording and any available error or service information.
Document:
- Exact error text
- Error code
- Startup stage
- Whether the fault is repeatable
- Power source in use
- Battery configuration
- Whether the failure follows a specific accessory
Do not replace the specific error with a generic note such as “would not work.”
Expected: Any startup fault is captured accurately enough to support further service evaluation.
Perform Approved Performance Verification if Startup Is Restored
A device that starts after reseating batteries, substituting power components, or correcting an external connection should not be returned directly to clinical use.
Perform the applicable approved LIFEPAK 35 operational and performance checks according to organizational procedure and current Stryker service documentation. Stryker publishes a LIFEPAK 35 Performance Inspection Procedure for device evaluation.
Expected: The device starts repeatedly, remains powered, and passes required operational checks.
If startup remains intermittent or any required test fails, stop and escalate.
If the Problem Persists
If the LIFEPAK 35 still will not start after verifying:
- Patient safety and device removal from active use
- Exact failure behavior
- External condition and physical damage
- Battery installation
- Known-good battery power
- Functional AC source
- AC Power Adapter connection
- Minimum external accessory configuration
- Controlled power reset
then common external causes have been ruled out and the fault is likely internal or requires manufacturer-level service evaluation.
The device should be:
- Removed from service
- Labeled Out of Service
- Sent for repair or bench evaluation
Do not proceed into deep internal disassembly, board-level troubleshooting, or undocumented component replacement unless authorized, trained, and working under appropriate current service procedures.
Knowing when to stop is proper troubleshooting.
Clinical Use Tip
Never troubleshoot a LIFEPAK 35 startup problem while an active patient depends on the device. Move care immediately to another verified defibrillator, then evaluate the failed unit in a controlled environment.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
"Clinical staff reported the Stryker LIFEPAK 35 would not complete startup and could not be placed into service."
Cause
What was observed during troubleshooting.
Example:
"Found the device failed to power on with the installed battery but started normally after substitution with a charged known-good LIFEPAK FLEX battery."
Resolution
What action was taken.
Example:
"Removed the suspect battery from service, verified repeated LIFEPAK 35 startup with known-good power, completed required operational checks, and returned the defibrillator to service."
Helpful Details to Include (If Known)
- Outlet tested
- AC Power Adapter inspected
- External power indication observed
- Original battery configuration documented
- Batteries reseated
- Known-good battery substituted
- Battery contacts inspected
- External accessories disconnected
- Exact startup behavior recorded
- Error message or code documented
- Indicator lights documented
- Unusual sounds documented
- Unusual heat or smell documented
- Physical or liquid damage documented
- Repeated startup attempts verified
- Performance inspection completed
- Final device status documented
Final Thought
A defibrillator startup failure requires a patient-safety-first response and disciplined isolation of external power, battery, connection, accessory, and environmental causes. Escalating an unresolved or intermittent startup fault is appropriate Clinical Engineering practice, and detailed CCR documentation improves both repair efficiency and future failure trending.
That is successful troubleshooting.