[GUIDE] Fix iMac flickering and dark screen problems out of warranty

OK, went ahead and decided to go a bit further. Since I also had the clouding issue, I decided I´d fix both problems at once.

Search for "iMac 27 clouding fixed" on Youtube for a step by step process of the removal of the metal bezel, to expose the glass layers of the screen where dust accumulates.

Going further is even easier, since it just involves removing the screws off the remaining plastic bezel, and snapping some tabs, to undo the whole thing. At this point you have to be extra careful with the flat cables that hang off the top of the pane (digitizer ?)

this will expose both LED bars, which are below a plastic piece that runs from side to side, which has a silver coating or sticker to divert the light upwards (actually, I think this is the responsible of the fault, since it appears that both ends "press" against both connectors.

By removing a few screws that hold the light bar, you´ll have total access to the connector (which was completely off). This way I managed to weld the same connector back in place. I also reinforced it with epoxi to give it some extra strength. Besides, I cut off the tabs that surround the connector to prevent the apparent pressure that caused the problem.

So now I have my iMac 27 back to its original state, with an evenly lit screen and cloud free !

PS: I had a bit of a scare, since when I plugged it back on for the first time, 1/4 of the screen showed colored vertical lines, as if a flex cable had been damaged. At this point I almost burst into tears since I noticed that the LED fix had worked... but ruined the screen along the road. Decided to pull the screen back out and checked on the two flex cables that run below the metal plate that sits on the back of the panel protecting some electronic boards. Removed and reattached them, assembled everything back together, crossed my fingers and pushed the power button. Big weight off my shoulders when I saw that pristine white loading screen !!!

Hi guys.

Last friday I decided to give my last try on fixing this problem.

After tried the "pressing" solution, I gone further and disassemble the display peace. So I couldn't have enough acesses to soldering back the connector neither to soldering cables direct on the board.

Encouraged by the @Cvitanic words, I decided to go a bit further too.

I made this monster and imposible soldering with a traditional soldering tip and a old solder. Can't believe I got it yet!

To reinforce the cables and also to isolate the wires, I used some epoxi, as @Cvitanic recomended.

I took some pictures from my adventure (see it bellow).

Here in Brazil we call this kind of "tricky but usefull fix", this "jerry-rigged stuff", this "MacGyver Ninja solutions", GAMBIARRA. You can have little fun googling it.

Last tip: be very carefull on cleaning the inside panels of the display and on puting back the plastic frame. In my experience, after puting everything back again, I noticed a little hair on the middle of the screen! Also, noticed some little shadows comming from the edges. This is probably caused by the misalignment of the plastic parts inside the plastic frame. It is little tricky to put all together back again. It seems like the plastic frame have some bevels to accommodate this plastic parts (these are like sheets of thin plastic).

Realy have to thank @Cvitanic for your key contribution and, obviously, to @Kaos2K for starting this thread and identified this unbelivable problem.

Thank you guys!!

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Hey guys,

today I tried with some friends do the soldering solution, like Kaos2K.

I have a friend how already made some soldering stuff, but, unfortunelly, for my luck, he can't make the service.

The hole is very small and some things don't help to make, some contacts plates start to get out from the hole D:

I don't lost all my hope, I will see if somebody can help me in my town, because, pay R$ 2.200,00 (~ US$ 900,00) for a LG screen is not a way for me.

There have been a few temporary fixes having to do with applying pressure at the connecter in various ways. I'm skeptical that these will last long, but for those who have had success, I sincerely hope it lasts!

When I had my panel out (mid-2011 27" LG panel LM270WQ1) I could get the backlight to power on briefly with slight finger pressure, which to me confirms that the solder joints have indeed broken. Trying to get power to the backlights by applying a little pressure to a broken solder joint just doesn't seem like a fix to me. If I can't get resolution through Apple, I'll try soldering.

Afterwards, I filed a bug report/issue online @ Apple, and also emailed Tim Cook (Google it), and the next morning I got a call from an agent at Apple Corporate Executive Relations (PR). While no resolution was offered by the agent, the action did create a case number, or record of the complaint. He sent a confirmation email which I replied to with photos documenting the affected panel & dimmed screen & computer serial#.

I think it's important for Mac users experiencing this issue to contact Apple directly and register a hardware issue complaint. Be thorough and polite. Posting on forums isn't enough. Fixing it yourself and getting on with life, while simpler in most cases, doesn't help pressure Apple to take responsibility for the components they use, or to tighten up their component testing protocol.

If it comes down to a class-action case, Apple will have to reveal how many complaints they've received to the court. Until a case comes to trial, enough legitimate complaints may force Apple to resolve the issue on it's own. I don't know if my case will be resolved. I do know that the dim screen is a nuisance and it places an asterisk after the iconic "Think Different*"

Greetings,

My earlier attempt at a fix to this problem using a japanese chopstick didn't last. The dark side of the screen returned and the screen would often go completely blank. Hitting the on/off button repeatedly often would bring the screen back but got very annoying. So, with much trepidation, I began the repair as Kaos2K and Gerry Sweeney... and it worked! But, this is not for the faint of heart. I was not an experienced solderer and this was a challenging job but it can be done. Here are some pointers:

1. Definitely watch Gerry Sweeneys youtube video. Its slow to start but its easy to skip ahead:

http://www.youtube.com/watch?v=gSzmyqQFZ2M

2. I bought a microsoldering kit from RadioShack for about $40. It had everything needed, notably had fine tips and flux core solder. It was only a 20 watt soldering iron and some in this forum expressed concern in this regard but it did the job just fine. http://www.radioshack.com/product/index.jsp?productId=34760766

3. Practice soldering. I like the videos referred to earlier in this forum:

http://www.youtube.com/watch?v=I_NU2ruzyc4

http://www.youtube.com/watch?v=3NN7UGWYmBY

Use the 30 guage wire wrap as suggested earlier. Practice joining two pieces of wire. The approach I used was to "tin" the wire initially; place a small amount of solder from the iron onto the wire. Let it cool; then hold the two wires together and heat them briefly to mobilize the solder. With practice this gets easier.

4. Buy a strong lamp with built in magnifying lense. I got mine at OfficeMax for $40 but they had some ugly ones for $25. There is no way I could have done this work without magnification and a bright light.

5. If you are not sure how to remove the LCD screen see this video:

http://www.youtube.com/watch?v=SDciJHx4II4

Its not very difficult but there are 4 plugs that need to be removed. There is one that I had a hard time with, a gold one. I eventually bent the silver wire holders off on each side. Keep trying, you can get it.

6. You have to access the plug and clean the plastic out as Gerry describes in his video.

7. Inside the plug hole are 6 metal contacts; you need to solder a wire to each contact. I did this by "tinning" the wire first, holding the wire in place, then briefly touching the wire with the iron to mobilize the solder. A second is

long enough. Too long and you'll start removing all the wires you've previously stuck. I had very little solder on the wires; too much and you will risk shorting out to the next wire. I gave each wire a gently tug to make sure it was firmly in place. Once I got the hang of it it went fairly quickly. Once all the wires are in place I tested each adjacent wire with a volt meter to make sure they weren't shorting out. Don't try to remove solder with copper desoldering braid... you will just pull of all the wires you have attached. Get it right the first time or clean everything of with desoldering braid and try again.

8. With that done, the other end of each wire needs to be solder to the white female end of the socket. Gerry's video shows this step well. There is less than a millimeter to work with but if you've gotten this far this is the easy part. Once done I put electrical tape on both sides of the socket to make sure it doesn't short out. I was very worried about wires pulling off the solders during reassembly so everything was carefully taped down.

That's about it. The whole process took about 5 hours with a few breaks and worked the first time. I figured my odds of succeeding were less than 50% but I figured if it didn't work I was getting a new computer. I've heard there is no guarantee that replacement screens won't have the same problem.

I have signed up for the class-action lawsuit and a lawyer called me about a month after I signed up on their website. I would give a link but it seems these are getting censored. A quick web search should direct you if interested. The lawyer said it is a long shot but these things often settle out. In general, I don't like class action lawsuits as it is only the lawyers who benefit (30% of the total settlement!). But in this case, I am on board. Best of luck to all.

Ok, i can confirm that this is mostly the same issue as with the LED Cinema Displays MDP/Thunderbolt when having flickering and/or no backlight at all, since they got the same old crappy LG Panel inside as the iMac. So first of all, the Cinema Displays show different symptoms than the iMac because of the Logicboard that shuts off both LED strips when one of them fails. In my case (Cinema Display 27 inch MDP) it was the bottom right connector which had minimum three disconnected/unsoldered pins. So i took the whole display apart and resoldered the connector. You should definitely get yourself some thin rubber gloves and an air compressor to get rid of the dust when reassembling this piece of… Anyway, the symptoms i had was that i had to first plug the upstream USB and MDP cable and then replug the power cord a few times before the flickering turned into a working backlight. Sometimes it was working for 10 Minutes and sometimes even for more than five hours, depending on the room's temperature. After checking Voltage of the Logicboard and Power Supply (also transistors and caps) i thought it can only be the LED section, and after finding this thread i knew it for sure. So, nice finding Kaos2K!!!

After having so much problems with these **** LG panels, i'm asking myself why in **** does apple still use them for their products? Even the current Thunderbolt displays got these panels inside. A question apple will probably never answer, huh?