The screen is dark on my MacBook air (13" early 2015), but by shining a light through the apple logo I can see that the screen pixels are working. Connecting to an external display (and external keyboard and mouse) shows that the computer is otherwise working fine.
Based on this question [post|629944] I tested the "P" fuse shown (which appears in the same place in the 2015 model as in that 2013 one); I think the fuse is ok: I see continuity across the fuse, and, when powered on, 8.47 volts on both sides.
Not having realized that backlight can go wrong separately from the LCD screen, I already bought and installed the $275 replacement screen ( [product|IF188-096] ). There is no difference in the backlight behavior between the old and new screen. But I can say that the LCD connector looks very clean.
What else can I test or do to narrow down why the display backlight isn't working?
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Edited Oct 20 2022 with some images:
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outside of logic board: [image|2762046][image|2762047]
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close-up of LVDS connector: [image|2762063][image|2762064][image|2762065]
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inside of logic board: [image|2762050][image|2762052][image|2762053]
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close-up of backlight IC: [image|2762055][image|2762056][image|2762057][image|2762058]
The screen is dark on my MacBook air (13" early 2015), but by shining a light through the apple logo I can see that the screen pixels are working. Connecting to an external display (and external keyboard and mouse) shows that the computer is otherwise working fine.
Based on this question [post|629944] I tested the "P" fuse shown (which appears in the same place in the 2015 model as in that 2013 one); I think the fuse is ok: I see continuity across the fuse, and, when powered on, 8.47 volts on both sides.
Not having realized that backlight can go wrong separately from the LCD screen, I already bought and installed the $275 replacement screen ( [product|IF188-096] ). There is no difference in the backlight behavior between the old and new screen. But I can say that the LCD connector looks very clean.
What else can I test or do to narrow down why the display backlight isn't working?