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Processore quad core Intel Core i7 da 2,0. 2,3 o 2,6 GHz (fino a 3,8 GHz con Turbo boost) con 6 MB di cache L3 condivisa.

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Display Backlight not working after replacement.

So I replaced the display assembly (thanks for the great tutorial), and it worked fine for 2 days but it suddenly stopped working, after some debugging I noticed that if I shine a light behind the Apple logo the screen can be seen correctly and if I connect and external monitor it works great. I've read it my be a fuse, cable or conector but I'm not sure how to test them. My board is 820-3787-06.

Thanks

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Rispondi a questa domanda Anch'io ho questo problema

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If you need a closer lookup of any part just tell me :)

da

FWIW the old screen worked before (it had damage) I connected it right now and it has the backlight problem too.

da

Tried a PRAM reset? If not, then could be a blown backlight fuse any history liquid damage drop damage? If you need board level repair, I can always help you out peep bio for that, but first thing is to try a PRAM reset.

da

I've done PRAM and SMC reset it didn't help. It was liquid damage

da

Sounds like a board problem then. Unless you have a bad screen, but if the old one is doing it, then I'd go backlight problem

da

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This shows the location of the backlight fuse. Check it with a multimeter. Should measure 0 to 1 ohm. If it doesn't, you're looking at a logic board replacement and/or component level repair.

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Ok so yesterday I investigated a little more, and using the datasheet I just uploaded:

Fuse F7700: Continuity OK

U7701 EN: 3.29V

U7701 PWM: 3.27

PPBUS_SW_LCD_BKLT_PW: 11.58V

BLKT_SD: 11.42V

LCD_BKT_EN_L: 11.4V

C7726: 5V

BKL_SW: 0

BKL_FB: 0

BKL_FET_CNTL: 0

PPBUS_SW_BKL: 0V

PPVOUT_S0_LCDBKLT: 0V <---- I know this should be 55V!

da

I think either it's Backlight Driver (U7701) or Transistor(Q7706)

da

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LCD_BKT_EN_L: 11.4V is enable … so ist Must be 0v for Turn on

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Adrian Rangel sarà eternamente grato.
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