Manual for LM55SI (W)

Manual for LM55SI (W)

Brand: Mitsubishi

Category: Monitors

Document Type: Manual

Language: EN

Uploaded: Nov. 21, 2025, 8:56 p.m.

Warranty Information

Consult dealer for installation work. Product warranty does not cover damage caused by improper installation.

Main Power Switch

Switches the main power on/off. Within 2 seconds after turning off the power, do not turn off the main power switch, disconnect the power cord, or turn off the breaker. If the AC power is turned off immediately after the power-off operation, OSD settings may reset.

Remote Control Sensor and Power Indicator

Receives signals from the remote control. Indicator shows power status (on, off, sleep mode, schedule standby, error).

Buttons

POWER button: Switches power on/off.

MUTE button: Switches audio mute on/off.

INPUT button: Switches video input.

+/- buttons: Adjust settings in OSD menu or audio volume.

UP/DOWN buttons: Navigate OSD menu.

EXIT button: Returns to previous OSD menu.

Speakers: Output audio.

Control Lock mode: Locks operation buttons.

Troubleshooting and error codes

Problem Solution
No picture
  • Check signal cable connection.
  • Ensure display card is seated correctly.
  • Verify Main Power Switch and computer power switch are ON.
  • Confirm correct graphics mode is selected.
  • Check monitor and display card compatibility.
  • Inspect signal cable connectors.
Power button does not respond Unplug and replug the monitor's power cord.
Image persistence Avoid displaying static images for long periods. Use moving screensavers or turn off the monitor when not in use.
Image is unstable, unfocused or swimming
  • Secure signal cable.
  • Use OSD Image Adjust controls.
  • Check monitor and display card compatibility and settings.
  • Change video mode to non-interlace and use 60 Hz refresh rate.
Image of component signal is greenish Select the YPbPr input connector.
LED on the monitor is not lit Ensure Power Switch is ON and power cord is connected. Check computer's power-saving mode.
RED LED on the monitor is blinking Contact Mitsubishi Electric service.
Displayed image is not sized properly
  • Use OSD Image Adjust controls.
  • Ensure correct mode is selected on the display card/system.
Selected resolution is not displayed properly Use OSD Display Mode to check and select the appropriate resolution.
No sound
  • Check speaker cable connection.
  • Ensure mute is deactivated.
  • Verify volume level.
Wireless remote control is not available
  • Check battery status and insertion.
  • Ensure remote is pointed at the sensor.
  • Connect IR sensor if issues persist.
"SCHEDULE"/"OFF TIMER" function is not working properly SCHEDULE is disabled when OFF TIMER is set. OFF TIMER resets if power is interrupted.
Privacy Policy