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| MacBook Pro A1990 No image repair | |
|---|---|
| Device | |
| Affects part(s) | |
| Needs equipment | |
| Difficulty | |
| Type | |
Problem description
When the MacBook does turn on but there is no image on the LCD. Backlight may be present but the screen is black
Symptoms
- No image on LCD
Solution
- Check the LCD cable and the connector on both the screen side and the logic board side.
- The backlight power line is right next to the eDP data line for the image.
- Any minor corrosion here results in 30 volts or more going to the displayport mux, U9850.
- U9850 is what the dedicated GPU and the CPU's integrated GPU go to before it goes to the screen.
- Unlike the 13" machine where the backlight voltage destroys the CPU, here it destroys a cheap chip.
- Replace U9850, and the screen cable, and the connector(on the screen side and the logic board side) and it will usually be fine.