Having just read something about it and answered another question like this on here. I would think that it is either your backlight or your inverter board, if the cable is okay and the connections are intact. Defective backlight may have the following symptoms: Screen flashes on red/pink and goes off. Picture stays on in red and slowly be come normal. Inverter error may have the symptom off Picture flickering with dim display and Picture flickering on and off. Apparently most screen backlight problems are caused by failing inverters and not the screen backlight itself. So it's hard to say for sure exactly what the problem is. But, the inverter lights up the light in LCD panel. Your cheapest fix is to replace the inverter located in the LCD panel and if that doesn't work then the light is burned out in the LCD panel itself. Just my 2cents and I am most certainly not a Mac person, yet. good luck