IntelliVue MX400/MX450/MX500/MX550

1. Make sure the patient is safe — swap in a backup unit if you need to.
2. Reproduce the complaint yourself and write down exactly what you see (screen, alarm, code).
3. Check power, battery, cables, accessories, and settings before ordering parts.
4. Then open the service manual above and follow its troubleshooting section.

Won't power on / AC LED dark source ↗

• Check the AC/DC-to-standard-system-interface cable and the main-board-to-power-switch/ECG sync board cable
• Power supply output 15 V ±3%
• Remove boards one at a time (I/O, advanced system interface, panel adapter, recorder/rack) to isolate; then the standard system interface board, then the main board

No green or red LED after pressing power source ↗

• Unplug AC for 20 min (power switch micro hung)
• Reseat or replace the power switch/ECG sync out board
• Strip to the minimum boards (remove IIT, WLAN, panel adapter, recorder, rack), then add them back one at a time

Red Error LED stays on, or LED alternates red/yellow (application software won't load) source ↗

• Disconnect external devices
• Support Tool over crossover cable → search for defective devices; in Boot mode save the status log, reload software and re-clone

Integrated display blank or dim source ↗

• Keep ambient temp 5–40°C; test with an external display on the video port
• Check the backlight/panel adapter cables; replace the panel adapter, Alarm LED board (light sensor), LCD, main board

Touch not working or touch position off source ↗

• Padlock on Main Screen key: press and hold to re-enable
• Service mode → Main Setup → User Interface → Touch Enable = yes
• Recalibrate: Service mode → Main Setup → Hardware → Touch Calibration

External display blank or external touch dead source ↗

• Option #J15 is required for DVI
• Check the cable and power; reconfigure MIB/RS232 drivers (Main Setup → Monitor → Hardware)
• Replace the Dual MIB I/O or advanced connector board

Alarm LEDs off or no test sound source ↗

• Check INOPs; check the main→panel adapter→Alarm LED board cables
• Replace the Alarm LED board (MX450–550) or panel adapter (MX400); speaker; main board

Normal boot sequence reference source ↗

• 0 s: red LED → 10 s: logo, green LED → 20 s: alarm LED cyan/yellow/red test + test sound → 22–30 s: measurements shown

Leads off / no signal (telemetry) source ↗

• Re-attach ECG leads
• Confirm transmitter is in coverage and batteries are good