Backlight won't turn on

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iMac Intel 27" Retina 5K Display (Late 2014 & 2015)

Model A1419 / EMC 2806 / Late 2014 or Mid 2015. 3.3 or 3.5 GHz Core i5 or 4.0 GHz Core i7 (ID iMac15,1); EMC 2834 late 2015 / 3.3 or 3.5 GHz Core i5 or 4.0 GHz Core i7 (iMac17,1) All with Retina 5K displays

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Sean H @hoganseand

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发帖于: 2016年11月30日

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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.

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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.

由 Dan 完成的 2016年12月1日

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

由 Sean H 完成的 2016年12月1日

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Dan @danj

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发帖于: 2016年12月2日

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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

由 Sean H 完成的 2016年12月2日

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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 声誉积分: 13 2 · Answer 1 · 2019-09-02T05:48:28-07:00

Jordan Shababy @jordanshababy

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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...

由 paul.lynch1 完成的 2021年3月8日

@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.

由 Dan 完成的 2021年3月8日

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iMac Intel 27" Retina 5K Display (Late 2014 & 2015)

Backlight won't turn on

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