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No backlight after display assembly replacement

Hi, can I get some help in finding the schematics and the Led driver on my MacBook Air ? The fuse is good but still no backlight on the device. The whole display assembly is replaced.

S/n C02J52DEDRVG

Best regards,

Vlad

Update

Hi oldturkey03,

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I really appreciate your effort in helping out a stranger.

The MacBook air was declared dead after a liquid spill and out of warranty. Now the MacBook works on an external display. After reading a bit on the net, I found the fuse which is marked with a "P" and if I measure it with an volt meter and set it to conductivity (diode sound measurement) it says that the fuse is ok. I'll try to attach the images from the MB and I would be grateful if you can help me find out the led driver location and the filter location.

Thanks in advance,

Vlado

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Update

Here is the

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2.0 GHz Core i7 (I7-3667U)

Intro Date: June 11, 2012 Disc Date: June 10, 2013

Order No: BTO/CTO Model No: A1466 (EMC 2559)

Subfamily: Mid-2012 Model ID: MacBookAir5,2

Std RAM: 4 GB Std VRAM: 384 MB*

Std Storage: 256 GB SSD Std Optical: None*

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If you need any guidance as for the location of the components, post some highres images of your logic board with your question. Use this guide Adding images to an existing answer to assist you with that.

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Hi to both of you,

First of all I wish to everybody a Happy 2014!

Sorry for replying a bit late but I finally found someone to replace the shunt and the wled driver which I have bought separately. He also checked the display.

The original display was LP133WP1 TJA7

The one that I got for replacement is LP133WP1 TJA3 and I hope that there is nothing wrong since both of them are LP133WP1?

However there is no output on the display yet. On the picture that I'm attaching here, I can see that there are 2 parts that have no voltage.

One is a circuit and the other looks like an SMD capacitor or a resistor? (since it's not closed circuit when tested with a voltmeter)

Do you by any chance have the schematics of the motherboard or can shed some light on what this parts are ?

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Hi again, I just saw that you already listed the part which I was wondering about and that's the FPF1007/8/9 on which there is no voltage. Do you know by any chance what is the small part on my last image ? It looks like a small capacitor or a resistor ?[image|310885]

The wled driver and the shunt monitor were replaced successfully and the original display was LP133WP1 TJA7 The one that I got for replacement is LP133WP1 TJA3

I messed up my comments again sorry :(

Thanks in advance,

Vlado

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Hello,

I have the same problem after display assemply replacement I have no backlight, the fuse is ok

I have a macbook air A1465 early 2015

Can you help me please ?

Thank's

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Vlado, two things you do want to check besides your fuse. The backlight driver is a TI LP8550 and is reference designator U9701, get the datasheet from here , but also check your backlight driver input current sense filter circuit. Here, the main component is INA211, reference designator U5490. The data sheet is available from here If it does not sense any current coming in, it may not tell the LED driver to work. Hope this helps, good luck.

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Update

Vlado, attached are the images that show the location of the two parts. Sorry had to mess with your images, but I need a bit higher resolution. Hope this is what you are looking for.

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Further Update

Vlado, good job on the enlarged image. I am not sure which component you were referring to, I listed the IC's so you can find the U5490 easier. U4600 is part of your USB Port Power Switch. U9000 is a The FPF1007/8/9 are low RDS P-Channel MOSFET load switch and has to do with your LVDS LCD connector, but not the backlight

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One More Update

Vlado, not exactly sure which component you are referring to, but I suspect you mean reference designator L9004 which is a FILTER CHIP 120 OHM 1.5A 0402 and is available from places like Digikey.com part number 490-4004-1-ND.

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4 Comments:

What OT3 says is good stuff, what you asked for. Why did you replace the display? Can you see images from the desktop etc... with a light shined on the screen? How do you know the fuse is good?? Macbook Air"s have backlight problems if the display is not replaced with the exact LCD, including revision. Did you replace the screen with the EXACT same LCD??

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Wow you are fast!

Sorry for the messed up images and I will try to make better ones.

Ok, I tried to see what's written on top of the U9701 and with a magnifying glass I think I can see something like a prism or maybe the Texas Instruments logo and:

21BT

D688

For the U5490

2561

TI 221

AHHF

I hope that this are the parts I need to check?

Thanks!

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Hi oldturkey,

I got the parts which had no voltage and I'll see the results soon.

Thank you so much for your help!

Vlado

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Hello,

I have the same problem after display assemply replacement I have no backlight

I have a macbook air A1465 early 2015

Can you help me please ?

Thank's

by

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Vlado will be eternally grateful.
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