Having a LCD Backlight problem iMac 21.5" late 2013 820-3302-A

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iMac Intel 21.5" EMC 2638 & EMC 2742 Late 2013

Model A1418 / Late 2013 / 2.7 & 2.9 GHz Core i5 or 3.1 GHz Core i7 Processor

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Justin @iphix

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Posted: Feb 22, 2017

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Having a LCD Backlight problem iMac 21.5" late 2013 820-3302-A

Hi techs

One of my costumers brought this iMac for repair, it was working fine while watching NetFlix and then, the screen went dark but voice still working.

I put the light on the LCD and I was able to see the apps, I plugged it to TV screen and it works just fine. Any help with that please?

Is there any fuse or a component for the backlight I need to check ( similar to the filter of iPad mayber ) ???

I've tested the outputs at the logic board feeding the flex cable which goes to the leds and found there's 0 volt on each!!!

Ahhhh!

Gotcha

It's FB9708

Many thanks for all

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@iphix what is the 820-XXXX number on your Logic board?

Feb 23, 2017 by oldturkey03

oldturkey03

820-3302-A

Thank you

Feb 23, 2017 by Justin

Hi dear,

Do you tell us what do you have done? Thanks.

May 2, 2018 by Marc

Hi there

I have at problem that might be in the same kategory, the screen at my imac 2013 is flickering random, shutting of picture- turning it on after 1/2 second or so.

Turning down brightness(light) is reducing the problem dramaticly.

Sometimes, the screen stay of, an comes first on again when the maskine reboots og goes into st-by.

External screen has no problems, neigher when main screen is constant off.

Anyone have an idea ?

Greetings /Jesper

Sep 30, 2018 by Jesper Godsk Nielsen

I`d test it with another new LCD _{this issue must be from LCD not from backlight circuit} keep me up to date with your results please.

thank you

Oct 7, 2018 by Justin

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oldturkey03 @oldturkey03

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Posted: Feb 23, 2017

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@iphix start by checking the backlight fuse F9700 for continuity. It is a 5A 32V fuse in a 0603 package. If you have conitinuity, then you do want to check it for 12V on either end of the fuse. Black to ground and Red to the contact on the fuse. You do of course need to power up the board.

Since you have power on the fuse, use the schematic to check the next components for power. test until you find the component that no longer shows power. Also, do not forget to check the backlight connector J9700

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Thank you

I have got 12.14v on both sides

Feb 24, 2017 by Justin

https://www.youtube.com/watch?v=A7jYNgmo...

Feb 24, 2017 by Justin

I have 11.76 on both sides of the dude . I have black screen

Dec 31, 2020 by Jose Gt

@Justin a question? If everything is measured and it is perfect, what would be the step to follow where would the problem be in the Flex?

because I have the same problem, the iMac 21.5 Late 2013 14.1 starts normally but you can see very little of the image of the apple when it is starting

Now, I did tests with another iMac 21.5 Late 2112 and I get the same problem, the screen is dark, it is impossible for me to believe that something on the Board has been damaged in both iMacs

Sep 16, 2022 by francis

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Hi there

I have at problem that might be in the same kategory, the screen at my imac 2013 is flickering random, shutting of picture- turning it on after 1/2 second or so.

Turning down brightness(light) is reducing the problem dramaticly.

Sometimes, the screen stay of, an comes first on again when the maskine reboots og goes into st-by.

External screen has no problems, neigher when main screen is constant off.

Anyone have an idea ?

Greetings /Jesper — Jesper Godsk Nielsen
I`d test it with another new LCD _{this issue must be from LCD not from backlight circuit} keep me up to date with your results please.

thank you — Justin
I have 11.76 on both sides of the dude . I have black screen — Jose Gt
@Justin a question? If everything is measured and it is perfect, what would be the step to follow where would the problem be in the Flex?

because I have the same problem, the iMac 21.5 Late 2013 14.1 starts normally but you can see very little of the image of the apple when it is starting

Now, I did tests with another iMac 21.5 Late 2112 and I get the same problem, the screen is dark, it is impossible for me to believe that something on the Board has been damaged in both iMacs — francis