MacBook Pro 15" late 2011 820-2915-B Graphicproblem internal Screen Black

[arash]

Hey Guys,
got a problem with a MacBook 15".
I have replaced the LCD, but it doesn't work.

External screen works fine, internal screen stays black.

 

[aprendiz]

Votage on pins 2, 4 and 40??? History??

 

[TCRScircuit]

LCD_PWR_EN present? Probably not because the GPU will probably be dead. Pin 246 of the GPU sends out the signal responsible to enable the lcd.