They have power but only color blue appear

• Input issue: TV isn’t receiving a signal → blue screen appears as a default “no signal” background.
• Backlight/T-con/main board problem: If the screen lights up but no image is drawn, one of the boards may have failed.
• Menu missing: If even the TV’s on-screen menu doesn’t appear, it’s likely a hardware issue, not just an input problem.

1. Test with multiple inputs
   Try HDMI, AV, or coax. If all show the same solid blue, the issue is internal.
2. Bring up the on-screen menu
   Press Menu on the remote or TV panel.
   • If the menu appears: input source problem.
   • If the menu does not appear: likely T-con or main board.
3. Power cycle
   Unplug the TV from wall power for at least 1 minute, then reconnect.
4. Check backlight
   In a dark room, shine a flashlight at the screen while it’s on. If you faintly see images, it means the backlight is working but video is missing.

• T-con board (connects main board to LCD panel) → common cause of “blue lit screen, no image.”
• Main board (signal processing) → if menus don’t display at all.
• Loose LVDS cable → ribbon from main board to panel.

⚠️ Since you mentioned repair requires nonconductive tools, you might be considering opening it. Be aware:

• Discharge capacitors before working inside.
• Avoid touching panel connectors with metal tools.
• The M215HW03 panel is fragile; cable reseating should be done gently.