2011 iMac no LCD backlight

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QuinnPedey Author

Level 1

6 points

2011 iMac no LCD backlight

Hi all,

I have a mid 2011 21.5" iMac and there is no backlight on the LCD.

If I shine a torch on the screen I can see all the icons faintly.

I can see everything fine on a external monitor though.

I thought the issue might be with the LED Backlight driver board so I replaced that and no difference, I can still only see the icons faintly with a torch.

I then tried another LCD and same result. Icons only visible faintly under a torch.

Now I'm starting to wonder, is it a faulty logic board? I read this post here https://www.techwalla.com/articles/mac-signs-of-a-bad-logic-board (scroll down to Display and Graphics Problems) (It's also not the GPU hence as I mentioned the I can see everything on a external monitor.

Does this look like a logic board issue? Everything I've done is leading me to this conclusion.

PS. All indicator lights go including the LCD communication one. So the iMac is detecting the screen.

Please let me know if you have some advise.

Cheers.

iMac 21.5", macOS 10.13

Posted on Feb 21, 2020 8:47 PM

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Answer 1

Kappy

Level 10

362,017 points

Feb 21, 2020 8:54 PM in response to QuinnPedey

Could be:

Failed GPU.
Bad motherboard.
Bad LCD display (common problem.) There was an extended warranty repair program but it has expired.
Bad backlights.

If you google any of these you will find information on repairing them. An LG replacement display will set you back about $400. Do not use a non-Apple display.

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Answer 2

Kappy

Level 10

362,017 points

Feb 21, 2020 9:09 PM in response to QuinnPedey

If you replaced the LCD display but still have a dark screen with noticeable video when shining a flashlight on the screen and you get video on an external display, then the video area is OK and so is the motherboard. That leaves the backlights. That would be my conclusion based on the stated evidence.

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Answer 3

QuinnPedey Author

Level 1

6 points

Feb 21, 2020 8:58 PM in response to Kappy

Hi,

As I mentioned I have already tried replacing the LCD (it was a genuine apple one for that model iMac) And the GPU is fine as everything works fine on an external display.

What does this lead you to conclude?

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Answer 4

QuinnPedey Author

Level 1

6 points

Feb 21, 2020 9:13 PM in response to Kappy

Thats what I thought. But I have already tried replacing the LED Backlight inverter twice and that made no difference. I also know that the LCD's and LED Backlight inverters work as I have a functioning iMac of the same model which I tested them all on. This is why I come to the conclusion of the Logic board. Did you check out the info In the link I provided in the original thread?

Cheers

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Answer 5

QuinnPedey Author

Level 1

6 points

Feb 21, 2020 10:26 PM in response to rkaufmann87

Hey,

So firstly this doesn’t help answer my question.

I already have a 2019 iMac. I can buy a new logic board for my 2011 Mac for $30 so I haven’t got anything to lose. It’s also very nicely spec’ed with 16gb ram 2 tb HDD and an ssd. So it would be nice to get it running again.

let me know if you have any ideas in regards of the issue you thing there is with the Mac

Cheers

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Answer 6

rkaufmann87

Level 10

148,600 points

Feb 21, 2020 10:14 PM in response to QuinnPedey

You keep pouring time and money into a $200 machine, no matter how much you put into it it's still a $200 machine. Have you considered replacing it?

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2011 iMac no LCD backlight

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