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What This Guide Helps With
Troubleshooting Capnostream 35 battery, charging, AC power, power cord, docking, or startup failure issues.
Step-by-Step Troubleshooting
Ensure Patient Safety First
If the Capnostream 35 is connected to a patient and is not powering on, charging, or maintaining power, remove it from patient use immediately.
Move the patient to another approved monitor before troubleshooting.
Expected outcome: Patient monitoring continues without relying on a questionable device.
Why it matters: Loss of power can interrupt EtCO2, respiration rate, SpO2, pulse rate, and alarm monitoring.
Verify the Reported Problem
Confirm the exact symptom reported by staff:
- Will not power on
- Powers on only when plugged in
- Battery does not charge
- Battery drains quickly
- Charging indicator does not appear
- Unit shuts off during use or transport
- Display flickers, reboots, or powers down unexpectedly
Expected outcome: The failure mode is clearly identified before parts or internal failure are suspected.
If the problem was caused by misunderstanding normal battery behavior, educate staff, document the finding, and stop.
Check AC Power at the Wall Outlet
Plug a known working device or outlet tester into the same outlet.
Confirm the outlet has power and is not controlled by a switch, failed power strip, tripped breaker, or emergency power issue.
Expected outcome: The outlet provides reliable AC power.
If the outlet is dead or unreliable, move the monitor to a working outlet, notify facilities if needed, document the issue, and stop.
Inspect the Power Cord and External Power Supply
Check the AC power cord and power supply for:
- Loose connection
- Bent or damaged prongs
- Cuts, kinks, or crushed cable insulation
- Missing strain relief
- Signs of overheating, melting, or odor
- Incorrect or non-approved power supply
Reseat the power cord firmly at the outlet, power supply, and monitor connection.
Expected outcome: The monitor receives stable external power.
If a damaged cord or power supply is found, remove it from use, replace it with an approved equivalent, retest the monitor, and stop if resolved.
Confirm the Monitor Shows External Power or Charging Indication
Connect the monitor to a known good outlet using a known good power cord and power supply if available.
Look for charging indication, AC power indication, screen activity, startup lights, or fan/display response depending on the device behavior.
Expected outcome: The monitor recognizes external power and begins charging or powering on.
If the monitor works with a known good power supply, the original power accessory is the likely cause. Replace the accessory and document the correction.
Allow Time for a Deeply Discharged Battery
If the battery is fully depleted, connect the Capnostream 35 to AC power and allow it to charge before attempting repeated startups.
Avoid rapid power-button cycling.
Expected outcome: The monitor eventually shows charging or powers on after receiving adequate charge time.
If the monitor begins charging normally, continue charging, perform an operational check, document the result, and return to service only if safe.
Check Battery Seating if Externally Accessible
If the battery is user-accessible without disassembly, verify it is properly seated and latched.
Do not open the device beyond normal battery access.
Expected outcome: The battery is fully seated and recognized by the monitor.
If reseating the battery restores operation, perform a charging and power-on check before returning the device to service.
Inspect the Battery Area for Damage
If the battery compartment is externally accessible, check for:
- Cracked battery housing
- Swelling
- Corrosion
- Liquid intrusion
- Damaged contacts
- Burn marks
- Unusual heat or smell
Expected outcome: Battery area appears clean, dry, and physically safe.
If swelling, heat, corrosion, liquid damage, or burning is found, remove the device from service immediately. Do not continue charging.
Test Battery Operation After Charging
After the monitor has charged, disconnect AC power briefly and verify whether the unit remains on battery power.
Observe for sudden shutdown, battery warning, rapid percentage drop, or reboot.
Expected outcome: The monitor remains powered and behaves normally on battery.
If the monitor only works on AC power, the battery may be depleted, failed, not recognized, or the charging circuit may require repair evaluation.
Check for Intermittent Power Loss
With the monitor powered on and not connected to a patient, gently move the external power connection and power cord.
Do not stress the connector.
Watch for flickering display, rebooting, charging status changes, or loss of AC indication.
Expected outcome: Power remains stable during normal movement.
If power cuts in and out, suspect a damaged cord, power supply, DC jack, connector, or internal power path. Remove from service for repair evaluation.
Perform a Basic Startup and Functional Check
Once the monitor powers on, verify:
- Display comes up normally
- Startup completes without repeated rebooting
- Battery/AC status appears reasonable
- No power-related alarms remain
- Buttons or touchscreen respond normally
- CO2 and SpO2 functions are available as expected
Expected outcome: The device starts normally and is ready for normal functional testing.
If startup fails, freezes, reboots, or power alarms remain, remove the monitor from service.
Return to Service Only if Power Is Stable
The Capnostream 35 should only be returned to service if it powers on reliably, charges normally, operates from AC power, and maintains battery operation as expected.
Expected outcome: The device is safe for patient monitoring use.
If any power instability remains, do not return it to clinical use.
If the Problem Persists
If the Capnostream 35 still will not power on, will not charge, shuts down unexpectedly, overheats, or only operates with certain cords or positions, common external causes have been ruled out.
Remove the device from service, label it Out of Service, and send it for repair or bench evaluation.
Possible internal causes may include a failed battery, charging circuit issue, damaged power input connector, internal power supply fault, system board issue, or liquid damage.
Knowing when to stop is proper troubleshooting. A capnography monitor with unstable power should not be used for active patient monitoring.
Clinical Use Tip
Do not troubleshoot battery or charging problems while the monitor is actively supporting patient monitoring. Move the patient to another working monitor first. Power instability can cause loss of respiratory monitoring and alarms without warning.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
"Staff reported the Medtronic Capnostream 35 would not power on and would not show charging when plugged in."
Cause
What was observed during troubleshooting.
Example:
"Found the external power supply connection loose at the monitor input; unit powered on normally after reseating and testing on a known good outlet."
Resolution
What action was taken.
Example:
"Reseated power connection, verified AC power and charging indication, powered unit on successfully, confirmed stable operation, and returned device to service."
Helpful Details to Include (If Known)
- Outlet tested and result
- Power cord inspected or swapped
- External power supply inspected or swapped
- Charging indicator present or absent
- Battery status shown on display
- Whether the unit powers on with AC only
- Whether the unit stays on when unplugged
- Any rebooting, flickering, or shutdown behavior
- Any unusual heat, smell, swelling, corrosion, or liquid damage
- Final device status: returned to service or removed from service
Final Thought
Battery and power-on failures should be approached from the outside in. Confirm patient safety first, then verify the outlet, cord, power supply, charging indication, and battery behavior before suspecting an internal fault. If the monitor cannot maintain stable power, escalation is the safest and most appropriate repair path. Clear CCR documentation helps show what was checked, what was found, and why the device was or was not returned to service.
That is successful troubleshooting.