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Asset Type
Electrocardiograph (EKG) Machine
Manufacturer
Model
Manual Reference
MAC 5500/MAC 5500 HD Resting ECG Analysis System Service Manual, Software Version 10, document 2046275-017G, Revision G, 31 January 2019.
Manufacturer Recommendation / AEM Status
The service manual does not establish one single interval for every maintenance activity. It lists maintenance activities at several different frequencies.
Manufacturer-Listed Frequencies
- Daily: Visually inspect the system and peripheral devices.
- Monthly or more frequently when needed: Clean and disinfect the exterior.
- Every three months or more frequently with heavy use: Clean the thermal printhead.
- Every three months: Perform a battery deep-discharge conditioning cycle.
- Annually: Perform current-leakage and ground-continuity testing.
- Before initial use, between acquisitions, when the battery is low, and after complete discharge: Charge the battery.
- Periodically, based on condition: Replace the patient cable and leadwires as necessary.
- Based on condition and test results: Replace the battery. No fixed calendar-based battery replacement interval is specified.
The manual states that failure to implement a satisfactory maintenance schedule may cause equipment failure and possible safety hazards. Regular maintenance is required regardless of equipment usage.
Battery Criteria
- At an indicated charge of 80% or greater, battery voltage should be between 15 and 24 V.
- Battery temperature greater than 45°C / 113°F indicates failure.
- Battery temperature more than 10°C / 50°F above ambient is a reason to consider battery replacement.
- Battery discharge capacity should be at least 2,000 mAh.
- A discharge capacity below 2,000 mAh is a manufacturer-listed reason to consider battery replacement.
Post-Repair Inspection
The service manual provides a component-specific checkout matrix. Depending on the component replaced or the work performed, required post-repair checks may include:
- Visual inspection
- Power-up self-test
- Simulated rhythm-strip recording
- Simulated ECG acquisition and recording
- Diagnostic testing
- Current-leakage and ground-continuity testing
- Option-specific communication or accessory testing
Power-supply, motherboard, enclosure, hardware-upgrade, and other listed repairs require electrical safety testing or other applicable checkout procedures before return to service.
AEM Status
If the facility performs this PM at a different interval or changes the manufacturer-listed activities, the change should be managed through the facility’s approved AEM program, documented risk assessment, maintenance history, and applicable regulatory requirements.
What This PM Procedure Covers
- Device, power cord, cable, connector, and accessory inspection
- Exterior cleaning
- Startup and basic user-interface operation
- ECG acquisition and print verification
- Writer and thermal printhead inspection
- Battery condition and operation
- Installed communication and input accessories
- Annual electrical safety testing
- Final return-to-service assessment
Required Tools and Equipment
- ECG simulator
- Leakage-current tester
- MT-1216-01 AAMI tester for 110 V systems or equivalent
- MT-1216-02 AAMI tester for 220 V systems or equivalent
- Standard hand tools
- #6 and #10 Torx drivers
- Phillips screwdriver
- MARQ 1 multifunction micro-simulator, when applicable
- TX609 precision dust remover, when interior cleaning is performed
- Lint-free soft cloth
- Approved cleaning and disinfection materials
- Thermal ECG paper
- SD card when external-storage testing is applicable
- Installed or compatible patient cable and leadwires
A facility electrical-safety analyzer may be used in place of the specifically listed tester when it can perform the manufacturer-listed test conditions and the substitution is permitted by facility policy.
Step-by-Step PM Procedure
1. Identify the Device and Configuration
Record the model, serial number, software version, installed acquisition module, communication options, trolley, barcode reader, card reader, and other configured accessories.
Expected outcome: Device identity and installed configuration match the equipment record.
2. Review Service History
Review the equipment record for unresolved repairs, intermittent failures, battery complaints, print-quality problems, liquid intrusion, or accessory issues.
Confirm whether the three-month battery-conditioning and printhead-cleaning activities are due.
Expected outcome: No unresolved condition prevents completion of the PM or safe testing.
3. Inspect the Housing and Exterior
Inspect the following:
- Case and display for cracks or other damage
- Exterior surfaces for contamination, corrosion, or evidence of fluid intrusion
- Display hinge and adjustment
- Writer door and internal-access latch
- Labels and safety markings
- Fasteners
- Trolley, mounting hardware, casters, and caster locks when present
Equipment requiring repair must not be used until repairs are completed.
Expected outcome: Housing, display, mounting, labels, and mechanical components are intact and secure.
4. Inspect the Power Cord
Inspect the complete power cord for:
- Worn, cracked, contaminated, or damaged insulation
- Exposed or frayed conductors
- Damaged strain reliefs
- Loose connectors
- Bent blades or a damaged ground pin
- Corrosion, oxidation, discoloration, or evidence of overheating
- Missing or illegible safety markings
Remove a damaged cord from service and replace it. Do not repair or modify the power cord.
Expected outcome: Power cord is intact, properly grounded, and free from damage.
5. Inspect the Patient Cable and Leadwires
Inspect the acquisition cable, patient cable, leadwires, adapters, connector pins, strain reliefs, and labels.
Check for:
- Cuts, cracking, brittleness, or exposed conductors
- Bent, recessed, contaminated, or corroded contacts
- Loose connector shells
- Damaged leadwire adapters
- Improperly matched or out-of-date disposable electrodes when supplied with the device
Expected outcome: Patient cable and leadwires are clean, secure, correctly identified, and free from damage.
6. Clean the Exterior
Turn the system off and disconnect accessories as appropriate.
Clean exterior surfaces using a cloth lightly moistened with mild soap and water. Disinfect using a manual-approved sodium-hypochlorite solution or wipe:
- Minimum 1:500 dilution of 5.2% household bleach, providing at least 100 ppm free chlorine
- Maximum 1:10 dilution
Dry the device completely before operation.
Do not immerse the device or cables. Do not allow fluid to pool around connector pins. Do not use ammonium-chloride products, abrasive cleaners, acetone, ketones, Betadine, alcohol-based exterior cleaning products, sodium salts, wax-containing products, autoclaving, or steam cleaning.
Expected outcome: Surfaces are clean, dry, and free from cleaning-related damage.
7. Clean and Inspect the Thermal Printhead
When the three-month activity is due, open the writer compartment and inspect the printhead and roller area.
Clean the thermal printhead with an alcohol-containing solution applied to a nonwoven, nonabrasive cloth such as Techni-Cloth. Do not use paper towels.
Inspect for paper residue, contamination, scratches, or damage.
Expected outcome: Printhead is clean and undamaged.
8. Verify Paper Loading and Writer Operation
Confirm:
- Correct paper size is selected
- Paper is installed with the holes on the left
- Paper feeds smoothly
- Writer drawer closes securely
- Perforations align with the tear bar
- Printing is dark, clean, and uniform
- No gaps, smearing, crushed paper, skewing, or paper jams occur
Perform a diagnostic writer test when print quality or paper transport is questionable.
Expected outcome: Paper feeds correctly and printed traces are legible, uniform, and complete.
9. Perform Startup Check
Connect the device to AC power and verify:
- Green AC-power indicator illuminates
- Device powers on normally
- Startup screen opens
- No unresolved error messages appear
- Display is readable
- Keys and controls operate without sticking
- Date and time are reasonable
- Device identifies the attached acquisition module
Normal opening of the startup screen indicates that the power-up self-test passed.
Expected outcome: Device completes startup without errors and reaches the normal operating screen.
10. Check the Display, Keyboard, and Speaker
Operate the display and all commonly used controls.
When indicated by equipment condition, repair history, or facility procedure, run the following manufacturer diagnostic tests:
- Pixel Verification
- Display test patterns
- Speaker test
- Keyboard test
Verify:
- No clinically significant missing pixels are present
- Test patterns display properly
- Speaker tone is audible
- Each key registers correctly
- Arrow pad and Shift functions operate properly
Expected outcome: Display, controls, and audible output function normally.
11. Verify ECG Acquisition and Recording
Connect an ECG simulator through the acquisition module and patient cable.
Perform:
- Simulated rhythm-strip recording
- Simulated resting ECG acquisition
- Printed ECG review
Verify:
- All expected leads are displayed
- Waveforms are stable and free from unexplained noise
- Lead labels are correct
- Rhythm strip records successfully
- Resting ECG completes successfully
- Printed waveform is legible and complete
- No unexpected lead-off or acquisition-module errors occur
For a MAC 5500 HD configuration, confirm that HD is displayed when a CAM HD is connected, Version 10 software is installed, and the HDMD option is activated.
Expected outcome: Device acquires, displays, analyzes, and prints a simulated ECG without errors.
12. Check Storage and Transmission Options
When configured and included by facility policy, verify:
- ECG can be stored internally
- ECG can be written to installed media
- SD card is recognized
- ECG can be transmitted to MUSE
- Ethernet communication operates
- Modem communication operates
- Barcode reader communicates
- Magnetic-card reader communicates
- Exercise device communicates
- External blood-pressure device communicates
Do not fail an unconfigured option merely because it is unavailable.
Expected outcome: Installed and supported options function as configured.
13. Check Battery Condition
Inspect the battery for swelling, leakage, heat damage, damaged contacts, or deformation.
Verify the system operates from battery power and transfers between AC and battery operation without an unexpected shutdown.
Review the following Battery Status information in system diagnostics:
- Percent charge
- Voltage
- Current
- Battery temperature
- Internal ambient temperature
- Charging status
At an indicated charge of 80% or greater, expected battery voltage is 15–24 V.
Battery temperature greater than 45°C / 113°F indicates failure. Consider replacement when battery temperature exceeds ambient temperature by more than 10°C / 50°F.
Expected outcome: Battery is physically intact, recognized, charges normally, and supports battery operation.
14. Condition or Capacity-Test the Battery When Due
The manufacturer recommends one deep-discharge conditioning cycle every three months.
When conditioning is due:
- Fully charge the battery.
- Disconnect AC power.
- Operate the device or run the Battery Discharge Test until the device shuts down.
- Reconnect AC power.
- Recharge the battery completely.
Do not perform repeated unnecessary deep-discharge cycles.
When a formal Battery Discharge Test is performed, the manufacturer-listed minimum discharge capacity is 2,000 mAh.
Battery discharge capacity:
Result = ______ mAh
Pass / Fail = ______
A result below 2,000 mAh is a manufacturer-listed reason to consider battery replacement.
Electrical Safety Testing
The service manual lists annual current-leakage and ground-continuity testing. Perform the applicable manufacturer-listed tests with the unit powered on and record every measured value and pass/fail result.
Ground Continuity
Test from the AC mains ground prong to the exposed metal ground lug or other applicable exposed grounded metal.
Ground resistance measured in ohms, manufacturer limit <0.2 Ω:
Result = ______ Ω
Pass / Fail = ______
Earth Leakage Current
- Forward polarity, normal condition: 300 µA
- Neutral open, forward polarity: 1,000 µA
- Neutral open, reverse polarity: 1,000 µA
- Reverse polarity, normal condition: 300 µA
Earth leakage measured in microamps:
Facility limit used = ______ µA
Maximum result = ______ µA
Pass / Fail = ______
Enclosure Leakage Current
- Forward polarity, normal condition: 100 µA
- Neutral open, forward polarity: 300 µA
- Ground open, forward polarity: 300 µA
- Ground open, reverse polarity: 300 µA
- Neutral open, reverse polarity: 300 µA
- Reverse polarity, normal condition: 100 µA
Touch/chassis leakage measured in microamps:
Facility limit used = ______ µA
Result = ______ µA
Pass / Fail = ______
Patient Leakage Current to Ground
- Forward polarity, normal condition: 10 µA
- Neutral open, forward polarity: 50 µA
- Ground open, forward polarity: 50 µA
- Ground open, reverse polarity: 50 µA
- Neutral open, reverse polarity: 50 µA
- Reverse polarity, normal condition: 10 µA
Patient leakage measured in microamps:
Facility limit used = ______ µA
Result = ______ µA
Pass / Fail = ______
Patient Leakage Current — Mains on Applied Part
- Forward polarity, neutral and ground closed: 5,000 µA
- Reverse polarity, neutral and ground closed: 5,000 µA
Mains-on-applied-part leakage measured in microamps:
Facility limit used = 5,000 µA
Result = ______ µA
Pass / Fail = ______
Record all electrical-safety values, not only the final pass/fail result.
15. Final Inspection and Return to Service
Confirm:
- Device is clean and completely dry
- All covers, fasteners, and connectors are secure
- Battery and paper are properly installed
- Patient cable and accessories are returned with the device
- No error messages remain
- ECG acquisition and printing are functional
- Electrical safety results pass
- Trolley brakes and mounting hardware are secure when applicable
- Device configuration has not been unintentionally changed
Expected outcome: Device is complete, functional, electrically safe, and ready for clinical use.
Pass / Fail Criteria
Pass
The device passes when:
- Physical inspection is acceptable.
- Power cord, cables, connectors, and accessories are undamaged.
- Power-up self-test completes without unresolved errors.
- Display, keyboard, controls, and speaker function normally.
- Simulated rhythm strip and resting ECG record successfully.
- Printed traces are legible and complete.
- Installed options operate as configured.
- Battery is physically intact and performs acceptably.
- Battery capacity is at least 2,000 mAh when formally tested.
- Ground continuity is less than 0.2 Ω.
- All leakage-current measurements meet the manufacturer-listed limits.
- No unresolved safety or performance concern remains.
Remove From Service
Remove the device from service when any of the following is present:
- Liquid has entered the device.
- Housing, display, mount, trolley, or internal-access mechanism is damaged.
- Power cord or protective-ground connection is damaged.
- Patient cable or leadwires have exposed conductors, damaged contacts, or unreliable performance.
- Device fails startup or displays an unresolved system error.
- Simulated ECG acquisition, recording, or printing fails.
- Battery is swollen, leaking, excessively hot, or unreliable.
- Battery temperature exceeds 45°C / 113°F.
- Electrical safety results exceed the manufacturer-listed limits.
- A repair or component replacement requires additional checkout that has not been completed.
Copy/Paste CMMS Work Order Procedure
Post-Repair Safety Inspection
Use the manufacturer service manual, facility policy, and approved AEM program to determine the final PM interval and return-to-service requirements.