Chosen Solution
I’ve got an issue with a MBP 15, with a screen that is dim though connecting it to an external display with the screen disconnected works like a champ (POSTs/Chimes and boots right on up). Here’s what I’ve done (swapped out/replaced): 4 different inverters with no change 2 different I/O boards with no change 1 cable change (one that connects to IO and logic/motherboard) 3 different LCDs (one of which I’m using as I type this) As I’ve stated before, if I disconnect the LCD/chassis and boot up with an external display connected it works fine. Connected, it’s D I M , but you can still see it boot in the right angle/lighting. Forgot to mention, also tried resetting PRAM and SMC as well. Model number is A1260, last three of serial are “1XR”. I’ve also ran the Apple Hardware Diagnostics from the factory disc, which doesn’t report any errors when hooked up to an external display with the display disconnected
Sounds like you have tried everything there is to try. When you say that you have changed the cable that connects I/O to logic board, are you referring to the LVDS cable that goes from the inverterboard to Logicboard? If you havent changed that Data cable, I would try that. If that doesn’t succeed, then you might be looking at a bad connector on the LogicBoard itself.
