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Manual Reference
OxiMax N-600x Pulse Oximeter with Alarm Management System Service Manual, document 10030881 Rev. B, December 2008; applicable N-600x Operator's Manual and OxiMax sensor instructions.
Manufacturer Recommendation / AEM Status
The N-600x requires no calibration. At least every 24 months, qualified service should inspect mechanical/functional condition and safety-label legibility, perform electrical safety tests, inspect fuses F1/F2 for 0.5 A, 250 V, and complete service-manual performance verification.
Replace the internal battery at least every two years. Replace a battery stored longer than six months or unable to recharge fully. A new fully charged battery provides at least seven hours only under the manual's stated conditions: no audible alarms, no analog/serial devices, and default brightness.
After visible damage or mechanical shock, perform the performance tests immediately. Except for battery charge/performance testing, the manual states performance tests should be the final operation before return to the caregiver.
Any interval/activity change should be managed under the approved AEM program, risk assessment, maintenance history, and applicable requirements.
What This PM Procedure Covers
- Physical, functional, label, cable, sensor, connector, and mounting inspection.
- Cleaning/disinfection, fuses, battery charge, and two-year battery replacement.
- POST, display, speaker, defaults, alarm ranges, silence, and volume.
- SRC-MAX pulse-rate, SpO2, modulation, and light tests.
- Sensor LED excitation, nurse call, and analog outputs when used.
- Class I Type BF electrical safety and return-to-service determination.
Required Tools and Equipment
- Nellcor SRC-MAX OxiMax tester and DOC-10 cable.
- Nellcor MAX-A sensor; DS-100A when required.
- Electrical safety analyzer meeting applicable IEC/AAMI requirements.
- Male 9-pin D connector with all pins shorted for applied-part leakage testing through DOC-10.
- Digital multimeter equivalent to Fluke 87 when output tests apply.
- Stopwatch.
- Soft cloth and commercial nonabrasive cleaner or 70% alcohol/water; 10% chlorine bleach/tap water when disinfecting.
- Correct battery and F1/F2 0.5 A, 250 V fuses when replacement is required.
- Facility-required personal protective equipment.
Step-by-Step PM Procedure
1. Confirm Identification and Configuration
Action: Verify asset tag, serial number, model, software version, institutional defaults, power configuration, battery age, sensors/cables, output and nurse-call use, mounting, and accessories.
Expected outcome: The device matches its record and configuration-dependent tests are identified.
2. Remove the Monitor From Clinical Use
Action: Transfer monitoring if needed. Power off and disconnect patient, sensor, data cables, and AC before cleaning/inspection.
Expected outcome: Maintenance proceeds safely without interrupting patient care.
3. Perform the 24-Month Inspection
Action: Inspect enclosure, LCD/backlight, LEDs, controls, speaker, inlet, cord/plug/earth pin, sensor/data ports, battery compartment, mounts, DOC-10, sensors, and accessories for damage, deterioration, contamination, corrosion, liquid intrusion, heat, or strain. Check safety labels and, through qualified service, confirm F1/F2 are each 0.5 A, 250 V.
Expected outcome: No mechanical, functional, electrical, accessory, label, or fuse defect is present.
4. Clean and Disinfect
Action: Lightly wipe surfaces with a soft cloth dampened with nonabrasive cleaner or 70% alcohol/water. For disinfection under policy, use 10% chlorine bleach/tap water. Follow sensor instructions. Do not spray, pour, or spill liquid on equipment or openings. Dry thoroughly.
Expected outcome: Equipment is clean, dry, and undamaged.
5. Review Battery Age and Condition
Action: Confirm age/history. Replace through qualified service if two years old, stored longer than six months, unable to recharge fully, damaged, or unreliable. Check terminal clips after replacement.
Expected outcome: The two-year requirement is met and connections are secure.
6. Charge and Check the Battery
Action: Connect AC, verify the monitor is off and the charging indicator is lit, then charge at least eight hours off or twelve hours on when full charge is required. With a full battery and monitor operating, disconnect AC; verify the AC indicator turns off, operation continues, and Low Battery is off. Reconnect AC.
Expected outcome: Charging and AC/battery transition are stable. Use the approved battery-performance procedure if runtime certification is required.
7. Perform the Power-On Self-Test
Action: Connect AC with no other cables and power on. Within ten seconds verify all LEDs, pixels, and backlight illuminate; indicators remain lit two seconds; NELLCOR/software version display; a three-beep tone followed by a one-second beep sounds; and normal operation begins.
Expected outcome: POST, display, backlight, indicators, speaker, and startup pass.
8. Verify Defaults, Alarm Ranges, and SatSeconds
Action: Record institutional defaults. Follow the service-manual sequence to verify adult/neonate selection, alarm ranges, selection beeps, and SatSeconds cycling OFF, 10, 25, 50, 100, and OFF. Restore institutional settings.
Expected outcome: Controls/ranges work and no unauthorized default change remains.
9. Verify Alarms, Alarm Silence, and Audio Volume
Action: Create SpO2 and pulse alarms. Verify pleth tracks pulse, pulse tone is audible, values flash, and alarm sounds. Verify a 60-second silence: indicator lit, values flashing, pulse tone audible, alarm returns at approximately 60 seconds. Verify 30/60/90/120-second choices and OFF only if ALLOW OFF is enabled. If OFF is enabled, verify flashing silence indicator and three-beep reminder at approximately three-minute intervals. Cycle alarm volume 1-10 and pulse-tone volume, then restore settings.
Expected outcome: Audible/visual alarms, timing, reminders, and volume controls pass.
10. Perform the Sensor LED-Excitation Check
Action: Connect DOC-10 and MAX-A. With the sensor open, verify bright LED. Slowly close it and verify intensity decreases; reopen and verify it increases.
Expected outcome: LED intensity modulation responds normally.
11. Perform SRC-MAX Functional Tests
Action: Connect SRC-MAX through DOC-10 and complete all four tests in sequence:
- Pulse rate: 60 selection displays 57-63 bpm; 200 selection displays 197-203 bpm.
- SpO2: 75% selection displays 73-77% with expected alarm; 90% selection displays 88-92% without low-SpO2 alarm.
- Modulation: waveform changes from approximately 1/2-inch peak-to-peak at low modulation to approximately 1 inch at high modulation while values remain in range.
- Light: after light-level change the waveform may initially flatline, then must recover; repeat range/modulation checks.
Expected outcome: Exact ranges and expected waveform/alarm behavior pass.
12. Verify Nurse Call and Analog Outputs When Used
Action: Follow the service-manual setup:
- RS-232 nurse call pins 5/11: +5 to +12 VDC in alarm; -5 to -12 VDC while silenced.
- Solid-state nurse call in alarm: pins 8/15 at 1 megohm or greater; pins 7/15 at 60 ohms or less. States reverse without alarm.
- Analog SpO2/BPM/pleth: +1.0 VDC and 0.0 VDC selections within +/-0.025 VDC.
Restore normal output configuration.
Expected outcome: Configured outputs meet listed values.
13. Perform Electrical Safety Testing
Action: Test as Class I Type BF using applicable standards. Connect applied-part leakage through DOC-10 using the shorted 9-pin connector.
- Ground integrity: 0.1 ohm or less.
- Earth leakage: IEC 500 microamps normal; 1000 microamps fault. UL 300 microamps normal; 500 microamps fault.
- Enclosure leakage: IEC 100 microamps normal; 500 microamps fault/reversed conditions. UL limit shown: 300 microamps.
- Patient applied risk current: 100 microamps normal; 500 microamps fault.
- Patient isolation risk current: 5 mA, normal and reversed polarity.
Use the exact applicable standard, region, manual edition, and facility criteria.
Expected outcome: Every required test passes.
14. Complete the Return-to-Service Review
Action: Confirm inspection, labels/fuses, cleaning, battery, POST, settings, alarms/audio, sensor excitation, SRC-MAX, outputs, electrical safety, and restoration all pass with no unresolved fault.
Expected outcome: The N-600x is ready to return to service.
Electrical Safety Testing
Electrical safety is required at least every two years and after applicable repair because the N-600x is Class I Type BF mains-powered equipment. Record exact analyzer results, configuration, standard, and limits.
Pass / Fail Criteria
PM Pass Criteria
- 24-month physical, functional, label, fuse, and accessory inspections pass.
- Battery replacement is current and charging/battery operation pass.
- POST, display, backlight, indicators, speaker, controls, alarm ranges, and SatSeconds pass.
- Alarms, silence timing/reminder, alarm volume, and pulse tone pass.
- Sensor LED excitation passes.
- SRC-MAX displays 57-63 bpm, 197-203 bpm, 73-77% SpO2, and 88-92% SpO2 as applicable; modulation/light response passes.
- Nurse call and analog outputs pass when used.
- Ground and applicable leakage tests pass.
- Settings are restored with no unresolved fault.
Remove From Service Criteria
- Damage, deterioration, illegible labels, incorrect fuses, liquid intrusion, or accessory damage affects safety/performance.
- Battery is overdue, cannot recharge fully, or is unreliable.
- POST, display, speaker, alarm, controls, SatSeconds, audio, or sensor excitation fails.
- Any SRC-MAX range or modulation/light response fails.
- Configured nurse call or analog output fails.
- Electrical safety fails.
- Settings cannot be restored or a fault remains.
Copy/Paste CMMS Work Order Procedure
Use the manufacturer service manual, facility policy, and approved AEM program to determine the final PM interval and return-to-service requirements.