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Model A1311 / Mid 2011 / 2.5 & 2.7 GHz Core i5 or 2.8 GHz Core i7 Processor

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iMac Screen Flickering after SSD installation

Hi there, my iMac screen currently flickers non stop at all brightness levels. The severity of the flickering is at its worse when the brightness is at maximum, but almost usable when at its lowest.

I have replaced the LCD backlight board, the display cable and the LCD display with a new display and cables. I'm completely stumped at this point.

The reason the Mac was opened in the first place was to replace the GPU which had died with a new one. Everything worked fine however one day it started flickering.

Any help would be massively appreciated !!

Update (07/08/2019)

@danj Hi Dan,

So I took the logic board out and managed to take a picture for you. Can't say that the LVDS port is damaged in any way.

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Any other suggestions, I have heard about filter caps on psu's going bad on other threads. But don't want to invest any more money until I can test something first.

Update (07/08/2019)

Hi @danj,

So I pressed the tabs down but I still get flickering.

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I will say even with the locking arm down on the display cable, it does not take any force at all to pull it out of the socket.

Any ideas?

Answer this question I have this problem too

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What does an external display look like? Does it show the same flickering?


@danj There is no flickering on an external display


@danj Hey Dan,

Unfortunately I've got none of the sort, best I have is a multimeter so I won't be able to go that in depth.


no Flickering on external display. works perfect. before the disassembling the lcd works fine. somebody has a fix? regards


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Most Helpful Answer

As your external display is not showing any defects that focuses the issue to the internal display and its connections to the logic board. I fear you may have damaged the LVDS connector on the logic board.

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When you pulled the display forward you may have yanked on the LVDS cable enough to distort the connector. Look down into the socket does one side look wider or pulled away?

Update (07/08/2019)

Looking at your image it does appear the locking tabs on each end are bent out (marked in blue)

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Place a Spudger behind the tab so you don’t go to far and carefully press it back down.

Update (07/08/2019)

At this point I would roll out the oscilloscope to see if I see any ripple on the LED backlight board. You’ll also need a LVDS, V-Scan power & thermal sensor extension cable set so you can have the display active on the system and yet full access to the internals. Do you have the schematics and board views? You’ll need them as well.

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Thomas Govern will be eternally grateful.
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