backlight turns on for a short period
I've replaced the backlight board by a brand new one, but unfortunately it didnt fix it. The sympthom is exaclty the same, i.e, right after the Mac is turned on, the backlight turns on for a short period (300ms lets say) and then turns off forever.
I suspect about some control signal. Since i already checked the ENABLE and PWM signals, the only one left is the VSync one.
I read on other forum that he mid 2011 no longer used a V-sync cable as it switched to an internal DisplayPort connection which integrated the V-sync into the main display cable.
Could a damaged vsync cable turn off the backlight?