My back light not turning on

Hallo everyone,

My macbook's backlight is not turning on please help. The display works fine when i connected to the external monitor. PLEASE guide for me to test : what can i proceed with testing the volatges ? and if there is any fuse failure.

I HAVE checked the fuse contunity it seems like backligh fuse is shorted(F9700). i am not able to read any volatges in PPBUS_SW_LCDBKLT_PWR , BKL_EN, like 2.7V

Is it because of fuse. need a suggestion before getting one ?

Please help.

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Firstly, having backlight on an external display wont prove the internal display feed is working.

The external display has its own backlight tubs that will be powered from the mains, whereas the data is coming from the MacBook pro.

If you have checked the backlight fuse on the main logic board, and it has blown, then something has shorted and caused it to blow.

is there any liquid damage on the board, or corrosion of any kind?

i'd suggest disconnecting the battery, then inspecting the LVDS cable (display cable that comes through the left hinge) to see if any of the pins on the left side of the socket are charred or damaged.

There is the possibility of replacing the fuse on the logic, although it is a component level repair, but its pointless doing this replacement without first tracing the cause of the fault. There will be some damage somewhere, unless it was an unusual power spike that blew it.

See what you can find, and if you find any damage, include some photos here and i'll see if i can help in any way.

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Hallo Jon,

Thank you for the answer!!

There are no liquid damage. To be frank i messed it up. Previously!! I observed that it wasn't charging, instead of trying it from another power adapter i thought its some fault in the connector and opened it (stupid decision) . During the inspection by mistake i touched my lcd connector to one of the resistor or capactior. I had removed my battery connector inside but i think there was a left over charge in the circuit!!! if i am right this made a short circuit and blown my fuse away. Yes i did check all the LVDS cable. Yes i know because of my foolishness now it cost me time and everything. I will send the pictures in the following posts.!!


To add to my previous comment!! at last i go to know that it was my power adapter probelm. I just had to check or replace my power adapter. To solve something i made my own mess!!


If it was a short that blew it, there is a chance that one of the small components is damaged.

Luckily, the fuse on this model is larger than on some other models.

It is 0.6 x 0.3 mm in dimension. So if you are good at soldering, you can replace it.

For finding the fuse, i'd suggest either using another dead board, or looking online for a replacement fuse. (somewhere like farnell for example)

It is an SMD 0603 2A fuse.

I've attached a photo in my post above with a photo of the fuse, just to make sure you are testing the right one. if you check for continuity with your voltage meter (beep test it), this will confirm if it is blown or not.


Finally, I know what this is all about. thanks.


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AIYAPPA M G will be eternally grateful.
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