Backlight won't turn on

Question

iMac Intel 27" Retina 5k Display (fine 2014 e 2015)

Modello A1419 / EMC 2806 / Fine 2014 o metà 2015. Core i5 da 3,3 o 3,5 GHz o Core i7 da 4,0 GHz (ID iMac15,1); EMC 2834 fine 2015 / Core i5 da 3,3 o 3,5 GHz o Core i7 da 4,0 GHz (iMac17,1) Tutti con display Retina 5K.

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Sean H @hoganseand

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Postato: 30 nov 2016

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Backlight won't turn on

So after I upgraded my late 2015 iMac 27" and put it back together, the backlight did not turn on when started up.

Its just the backlight because I can see everything on the screen if I shine a strong light on it. I recently looked at the diagnostic LEDs on the logic board and the 4th one will not light when starting up. That leads me to indicate the issue is with the backlight board.

Any thoughts on how i can fix that?

Or, could it be an issue on the display side like the connections? The connections were good from what I could see.

I can't seem to find any info in 2015 iMacs.

Risposto! Visualizza la risposta Anch'io ho questo problema

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Here's the collection of IFIXIT guides for your system: iMac Intel 27" Retina 5K Display Repair.

I would review them to see what you might have forgotten or mis-connected.

1 dic 2016 da Dan

Yeah i keep looking . Ive tried to re do the whole thing multiple times and have the same outcome

1 dic 2016 da Sean H

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Soluzione Prescelta

Dan @danj

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Postato: 2 dic 2016

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The only thing I can think of is you blew the backlight LED voltage regulator on the main logic board somehow. At this point I think you'll need to throw in the white flag and bring your system into an Apple Store or Apple authorized service center. Hopefully you can weasel your self into a free repair otherwise it could be expensive!

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Darn lol i didn't want to accept this fate but i was thinking the same thing

2 dic 2016 da Sean H

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Here's the collection of IFIXIT guides for your system: iMac Intel 27" Retina 5K Display Repair.

I would review them to see what you might have forgotten or mis-connected. — Dan
Yeah i keep looking . Ive tried to re do the whole thing multiple times and have the same outcome — Sean H
Darn lol i didn't want to accept this fate but i was thinking the same thing — Sean H

Jordan Shababy @jordanshababy Rep: 13 2 · Answer 1 · 2019-09-02T05:48:28-07:00

Jordan Shababy @jordanshababy

Rep: 13

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Postato: 2 set 2019

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Hello! So a few years later- I also have a 2015 that has no backlight. I went through replacing the logic board, power supply and LVDS and had the same results: 3 leds on and the 4th is off. The only thing I haven't tried is another LCD. Thoughts? Thanks for any help!

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did you get to the bottom of this? - I've got exactly the same situation.. screens works when strong light shone but no backlight...

8 mar 2021 da paul.lynch1

@paul.lynch1 - Sounds like you need someone to fix your logic board backlight circuit. I've seen a few of these for some reason the logic is more sensitive in this series.

8 mar 2021 da Dan

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iMac Intel 27" Retina 5k Display (fine 2014 e 2015)

Backlight won't turn on

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