820-2914 board no back light

[turbo]

macbook 17' 820-2914 board , no back light

known good screen and LVDS CABLE , TESTED
new lvds connector on board,

C9880 = 39v


still no back light


feedback connection good

any idea why no back light


Q9701 pin 1234 0.4v !

 

[jgraffis]

the machine is not detecting the screen. double check the screen connector. if ok then check for short to ground on all 30 pins( especially pin 1234).

 

[dukefawks]

Of course the screen is detected else there would be nothing on BKL line!

PWM is missing. PRAM reset done?

 

[turbo]

yes PRAM reset done , no result ... still no back light

 

[aprendiz]

What about PWM signal??