Chosen Solution
As the title says, the screen on my A1502 MacBook Pro only works with an external display plugged in. Without the screen plugged in the display is completely distorted and unusable. I have formatted the laptop and reinstalled software but it made no difference. Any idea why this is happening? Pictures for reference:
If the internal screen is always bad you have isolated the issue down as a physical failure within the display its self. There is nothing software wise that will alter things here. Time to replace the display assembly! I wish I could give you the rest of the story but I will need to know which system you have as the A1502 covers three different models, can you tell us which.
