Model A1311 / Mid 2010 / 3.06 & 3.2 GHz Core i3 or 3.6 GHz Core i5 Processor

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Why is screen black after replacing hard drive?

Hi,

I just replaced the hard drive on this 21.5" mid-2010 1Mac.

All went smoothly, except... the screen now stays black at startup.

The screen appears to be totally black. There is no evidence of any backlight activating.

I tested with an external display connected via mini-dv, which works fine.

The first 3 internal diagnostic LEDs all light up, but the 4th remains dark.

If LED 4 is ON it indicates "... that computer and LCD panel are communicating. This LED will be ON when computer is turned on and video signal is being generated. If LED#4 is ON and there is no image on display, then the LCD panel, the LED backlight board, or the cables between LCD and logic board or backlight board might be installed incorrectly, or need replacement."

Since LED 4 is off, I deduce my computer & LCD panel are not communicating.

I am hooping I can just get a replacement cable to fix this. Is there any further troubleshooting I can do to determine which cable to replace?

The video/data cable, the backlight cable and the vertical hold cable, all of which have to be removed for this upgrade. Perhaps one of them was damaged. My money would be on the video/data cable since this was a pain to re-connect... but is there any way to test?

Thanks,

ft.

Answer this question I have this problem too

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From a power off state, does the imac chime when you power up? If so (hearing the chime), are you saying that you do NOT at any time see a light grey screen with a dark grey apple logo about center of the screen?

Do you have a recovery disk? Try booting off of the recovery disk and see if you get the display to work its normal routine. Also, be listening if the optical disk is being accessed during this time.

Find a flashlight and shine it onto the screen to see if the backlight just happened to fail on you.

If still dark on the screen, then re enter the imac to verify that all the cables are attached and plugged into their appropriate sockets

Let us know what you find out.

Terrence.

Update

My apologies for misreading your post. Thanks for reviewing the facts again for me. As you know, when a system is working fine prior to an upgrade and fails in the aftermath of such upgrade then one can conclude that either the failure was only coincidental, OR that in the process of performing stated upgrade, that an unnoticed improper reassembly or damage occurred. I have observed that an lcd panel requires a data cable AND a cable to drive the lcd backlight. This was the reason i suggested shining a flashlight upon the screen to see if the panel was actually getting data. The reason for using an os x recovery disk was to ensure that display drivers was actually being loaded to drive the display and eliminating possible corruption or missing driver. But since you pointed out that the external DVI will drive an external monitor, I agree that booting from a recovery CD/DVD would not buy you anything. So, we are left with having to re examine the cables that were unplugged to remove / install the upgraded drive, looking for damaged cables or connectors OR cable to connector that was reversed upon reconnection. Good luck.

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As stated, the internal screen stays back at startup.

As stated, the computer works fine with an external display.

Why would the recovery disk make any difference whatsoever? And why does the optical drive matter?

Nothing shows with a flashlight on the screen.

All the cables are attached and plugged into their appropriate sockets.

Now, back to my question...

I am hoping I can just get a replacement cable to fix this. Is there any further troubleshooting I can do to determine which cable to replace?

Thanks,

ft.

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with the passage of time, can you update us as to what you might have discovered?

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I have the same problem and I have narrowed it down to the logic board or the connector on the logic board. I have replaced the backlight driver board and test the lcd itself as well as the cables. The only thing left on mine is the connector on the logic board or the logic board itself. If anyone has some input I would appreciate it.

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hi chad. with the passage of time, did you discover what the issue was and its fix?

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I also have the same problem, have tested the LCD and backlight driver board. Any ideas?

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I had the same problem: Only external video, LED 4 not lid. It was a faulty inductor on the main board. Look:

After HD changed, fuse (wall) tripped, no internal video, but external

Regards.

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I had the same problem on my iMac 27". Apple replaced logic board, video card and display and the problem would secure after several weeks or months. Very frustrating. I eventually replaced the machine and several months afterward decided to do a "nuke and pave." I completely reformatted the hard drive and installed a new OS. I have not had the black screen problem since then. The machine has been running smooth for several weeks with high graphics usage, i.e. FCP and video encoding. I am thinking now that this is not a hardware problem but a software problem and it must be some obscure driver or bad programming with the sleep command. Perhaps permissions or corruption.

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How ou formatted the hard drive with the black screen issue, you connected a external display to do this?

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from my reading of mbrassert's post, I can conclude that the Imac Logic board was replaced that a reformat and software reinstalled done some months afterwards.

Having viewed a number of youtube videos where the led backlight was an issue, most seem to point to a backlight surface mounted device FUSE was the issue.

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fishtech will be eternally grateful.
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