Unibody MacBook Pro models with 13" displays produced from 2009-2012.

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Dull display on MacBook Pro a1278

Hi frnds

Got a MacBook pro a1278 I'm getting very feable /dull display on the screen

Actually it's intermittent once in a while it gives bright display , wanted to access to displsy cable tried opening from screen end damged front glass however I'll replace it once I'm.able to fix this issue

I got 3.3v on screen fuse, 12.5 on pin3-4 LED BKLIGHT CONNECTOR of screen(b133ee7 v2) I'm not able to figure out pwm enable & brightness control signal(unlike regular led screens) pins from motherboard or screen.end

Any help would be greatly appreciated



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Pls any help would be greatly appreciated, rgds


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sry frnds before anybody was interested in answering my question and help me fix

i figured it out the problem,

i suppose nobody wanted to share the trade secret haha

however i learnt it hard way and indeed costed me cost to the front glass which i tried to remove n broke as

i wanted to chk whether cable and screen were ok

coming to solution i found out that IC location u9701 which is LP8550 is a led driver unlike our regular PC screen where backlight works using 19v / backlight enable & backlight PWM for brightness

this particular mac uses +Ve / backlight PWM sync and 6 Return signals for backlight and brightness which is driven by LP8550 connected via serial resistors

i did a flux and reheat of the IC now works perfectly hope this feedback helps somebody someday

great day


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Vasanth Kumar zal eeuwig dankbaar zijn.

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