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Asset Type
Electrocardiograph (EKG) Machine
Manufacturer
Model
Models Covered
ELI 150c only. The current OEM source used for this procedure is specifically the Baxter/Welch Allyn ELI 150c service manual. Do not apply internal power-test limits or disassembly instructions from this page to another ELI model without its model-specific manual.
Manual Reference
Baxter/Welch Allyn ELI 150c Resting Electrocardiograph Service Manual, REF 9516-177-50-ENG Y, revision 2026-05. Mortara-branded ELI equipment is now supported under Baxter/Welch Allyn branding.
Manufacturer Recommendation / AEM Status
The OEM recommends preventive maintenance annually and states that servicing is to be performed only by Baxter-authorized service personnel. This procedure preserves that annual interval and the manual's measured limits. It is not an authorization to open or service the unit. Follow facility policy, local electrical-safety requirements, and the current service documentation; do not extend the interval through an AEM program without a documented risk assessment and approval.
What This PM Procedure Covers
- Identity, configuration printout, service history, cleaning, enclosure, labels, connectors, cabling, writer mechanics, and internal condition
- Battery open-circuit and loaded voltage, OFF/ON current, AC charging behavior, and charger output voltage
- AC indication, display, writer test, ECG acquisition, keyboard matrix, ECG noise, and individual lead-failure indication
- Installed modem, LAN, WLAN, USB-host, and USBD communication options
- Required Class I, Type CF electrical-safety tests after the housing has been opened
Required Tools and Equipment
- Current ELI 150c service manual, test data record, and applicable operator documentation
- Calibrated multimeter/current meter and electrical-safety analyzer suitable for IEC 60601 testing
- 10-ohm, 20-watt power resistor for the battery load test
- 10-lead ECG simulator, AM12 or WAM patient input module, approved lead set, and snap adapters as required
- 10-lead shorting block (TF-0063 or equivalent) and lead-failure box (TF-0620 or equivalent)
- Smart thermal paper, Phillips No. 2 screwdriver, and approved hand tools
- FAT32 USB device and a correctly configured Baxter ELI Link receiving station/cables for installed communication options
- Lint-free cloth, mild detergent, or 80–99% isopropyl alcohol as permitted by the manual
Step-by-Step PM Procedure
1. Remove the Cardiograph From Clinical Use
Action: Confirm no patient is connected, mark the unit as under service, disconnect accessories, and move it to a controlled work area. Use antistatic precautions and qualified service personnel for internal tests.
Expected outcome: The cardiograph is safely controlled and no patient can be exposed to test signals or an open enclosure.
2. Verify Identity and Print Configuration
Action: Verify the unit is an ELI 150c. Record asset tag, serial number, location, software/configuration, installed patient input module, communication options, battery age/date code, and PM due date. Turn the unit on, print the device configuration, and attach it to the PM record.
Expected outcome: Physical identity, CMMS record, and printed configuration agree.
3. Review History
Action: Review prior PMs, repairs, drops, liquid events, battery or charging complaints, poor traces, paper-feed issues, lead-off complaints, and failed transmissions. Resolve open corrective work before return to service.
Expected outcome: Repeat failures and repair-triggered testing are identified.
4. Clean and Dry the Unit
Action: Turn the unit off and disconnect AC power. Clean according to the manual with a lint-free cloth and approved agent. Do not immerse the unit or use organic solvents, ammonia-based solutions, or abrasive cleaners. Prevent fluid entry and dry completely.
Expected outcome: The unit is clean, dry, and free of residue or fluid intrusion.
5. Perform External and Internal Inspection
Action: Inspect housing, display shield, AC inlet, patient connector, antenna and communication ports, writer door/latch/mechanism, labels, cord, plug, and accessories. When authorized to open the housing, inspect for contamination, fluid damage, battery leakage, debris behind the display, cracked/pinched/partly disconnected cables, loose hardware, and incorrect PCB fuse ratings.
Expected outcome: No damage, exposure hazard, contamination, leakage, loose connection, unreadable marking, or incorrect fuse is present.
6. Measure Battery Open-Circuit Voltage
Action: Fully charge the battery, disconnect AC, remove the upper housing/writer assembly as directed, disconnect the battery red lead, and measure battery voltage. Record battery age and reading.
Expected outcome: Open-circuit battery voltage is greater than 12.5 VDC.
7. Measure Battery Voltage Under Load
Action: Place a 10-ohm, 20-watt resistor in parallel with the battery and measure after approximately five seconds.
Expected outcome: Loaded battery voltage is greater than 11.7 VDC.
8. Measure OFF and ON Current
Action: Connect the current meter in series with the battery. With the unit off, record OFF current. Turn the unit on and record ON current.
Expected outcome: OFF current is less than 100 µA; ON current is less than 250 mA.
9. Verify Charging Current and Charger Output
Action: Apply AC power and verify battery current reverses polarity and decreases with time. Disconnect the current meter and measure charger output between the disconnected red battery cable and battery negative terminal.
Expected outcome: Charging behavior is correct and charger output is 13.0–14.0 VDC.
10. Reassemble and Check AC LED and Display
Action: Reconnect every cable and correctly reassemble the unit. Apply AC power and start the cardiograph. Inspect the display for clarity, missing lines/pixels, or flicker.
Expected outcome: The green AC LED remains illuminated; the battery indicator is clear while charging and white when fully charged; display text is clear and stable.
11. Test the Writer
Action: Verify the writer door opens, closes, and latches smoothly. From the main screen press Shift + Alt + RHY simultaneously. Inspect the test print and paper movement.
Expected outcome: The page prints and stops at the cue mark, perforation aligns with the tear edge, darkness is uniform with no gaps, gears do not skip, and paper tracks correctly.
12. Test ECG Acquisition and Keyboard Matrix
Action: Connect a known ECG signal through an AM12 or WAM, set a known rate and amplitude, press ECG, and confirm the key beep. Enter last name PARCFL8, then press F6 (Done), acquire, and inspect the 12-lead printout.
Expected outcome: The keyboard matrix is exercised, acquisition completes, and all 12 traces print correctly with uniform darkness.
13. Perform the ECG Noise Test
Action: Connect the 10-lead shorting block and adapter to the AM12 or WAM. Set gain to 20 mm/mV and print approximately one page of rhythm.
Expected outcome: No channel has more than 0.5 mm of noise when measured on OEM thermal paper.
14. Perform the Lead-Failure Test
Action: Connect the AM12 or WAM to a lead-failure box or patient simulator. Open each patient lead one at a time and compare the display with the expected lead message: right arm—LEADS OFF; left arm—LA OFF; left leg—LL OFF; V1 through V6—the corresponding V-lead OFF; all leads open—LEADS OFF.
Expected outcome: Every opened lead produces the correct indication.
15. Test Installed Communication Options
Action: For each installed modem, LAN, WLAN, USB-host, or USBD option, configure the required ELI Link receiving station/device, acquire a test ECG whose patient-name field identifies the transmission method, transmit it, and verify receipt and the transmitted mark in the unit directory.
Expected outcome: Every installed and used communication path transfers a complete record and is marked transmitted.
16. Perform Electrical-Safety Testing When Required
Action: If the housing was opened for repair or inspection, perform the safety tests described below using the applicable IEC 60601 method and limits.
Expected outcome: Earth leakage, enclosure leakage, patient leakage, and patient auxiliary current all pass the adopted standard and local limits.
17. Restore and Document
Action: Reconnect approved accessories, restore authorized settings, confirm date/time and normal operation, attach configuration/writer/ECG/noise printouts, record all readings and test-equipment IDs, clean the exterior, and document parts and disposition.
Expected outcome: The ELI 150c is complete and traceable, and is either returned to service or clearly removed from service.
Electrical Safety Testing
The ELI 150c is identified as Class I, Type CF. When the housing has been opened, the OEM calls for testing in accordance with IEC 60601. Use the limits in the currently adopted standard and facility procedure; the service-manual checklist names these tests but does not publish separate numerical limits:
- Earth leakage
- Enclosure leakage: because the chassis is fully insulated/nonconductive, test with 200 cm² conductive foil or equivalent; the AC earth is functional earth, not safety grounding
- Patient leakage: test the applied part using the Baxter AM12 patient cable
- Patient auxiliary current: test the applied part using the Baxter AM12 patient cable
The AM12 and WAM provide patient defibrillation isolation and are non-serviceable modules; the manual states that Hi-pot testing is not required for this cardiograph. Record analyzer identity/calibration, standard and edition, applied-part setup, polarity/fault state, readings, limits, and pass/fail.
Pass / Fail Criteria
PM Pass Criteria
- Correct ELI 150c identity/configuration; configuration printout attached; inspection and cleaning pass
- Battery open circuit >12.5 VDC; loaded voltage >11.7 VDC; OFF current <100 µA; ON current <250 mA
- Charging current reverses polarity and decreases with time; charger output is 13.0–14.0 VDC
- AC indication, display, writer, keyboard, 12-lead ECG, lead-failure messages, and installed communications pass
- ECG noise is ≤0.5 mm on every channel at 20 mm/mV
- All required electrical-safety tests meet the applicable IEC/local limits
Remove From Service Criteria
- Cracked/wet housing, battery leakage, exposed circuitry, damaged mains components, incorrect fuse, unreadable safety label, loose/damaged internal cable, or unresolved contamination
- Any battery/current/charger reading is outside the stated OEM limit
- Failed display, writer, keyboard, acquisition, trace quality, noise, lead-off indication, or required communication function
- Any required electrical-safety test fails or an opened unit has not received the required safety testing
Copy/Paste CMMS Work Order Procedure
Use the current model-specific OEM documentation and qualified biomedical service personnel. Internal power measurements expose an opened device and are not operator checks. Never connect a patient during service testing, and never return a failed or incompletely tested unit to clinical use.