asle," LED #1 + LED #2 + LED #3 + LED #4 = Power available, system is powered on, video card
found, and internal LCD found.
If fourth LED is not visible after power on:
• Verify internal DisplayPort cable connections between LCD panel and logic board
• Inspect LCD display cables for cable damage
• Verify external video functionality, and according to result check the following items:
If external display works then verify/replace the LED backlight board
If external display works then verify'''/replace the LCD panel'''
If external display does not work verify/replace the logic board" sounds like a bad LCD