27" iMac LCD screen information (this is nowhere else but here)

Discussion in 'iMac' started by one1, May 10, 2011.

  1. one1 macrumors 65816

    Jun 17, 2007
    Chattanooga, TN
    As with everything hardware with newer Apple stuff, lack of info means it's done the hard way or not at all. I've done it the hard way so you don't have to. The newer part number for the mid 2010 iMac screen doesn't even exist on the internet yet. (until now)

    27" Late 2009 Core Duo uses LG screen LM270WQ1 (SD) (A2)

    27" Mid 2010 i3, i5, i7 all use LM270WQ1 (SD) (C1)

    The difference is NEARLY none, except one single thing. They changed 1 plug for no apparent reason but to screw with you. The part numbers on the controller boards are the same, everything else is the same. They simply changed the connector. It's not stronger, bigger, nor better suited, it's just "different".

    You may notice the (A2) screen is beginning to pop up a few good places now, but the (C1) screen doesn't even exist on google. ......at all.

    To remedy this if you have to replace the screen, buy the (A2) screen and swap the controller board in question with your old one.

    The board with the WHITE PLUG is the Late 2009 Core DUO.

    The board with the BLACK plug is the Mid 2010 i3,i 5, i7.

    This plug can be seen in the pics below in the first picture the plug is closest to you in pic #1, small, and it is a 4 pin plug to the right of the copper square.

    This board is dead center at the top rear of your LG 27" screen. It's only about a 5 minute job.

    Attached Files:

  2. vladi macrumors 6502

    Jan 30, 2010
  3. flipster macrumors 6502a

    Mar 14, 2010
    I'm curious as to why they would change one simple little thing like that if it has no effect/benefit from the previous displays

    Nice find, btw
  4. one1 thread starter macrumors 65816

    Jun 17, 2007
    Chattanooga, TN
    I have looked the boards over and they are identical, there seems no need other than to sell a new board with the LCD if you swap them. One has a build date as late 2009 and one has a build date as mid 2010, otherwise identical.
  5. bruce302ford macrumors newbie

    Apr 14, 2010
    What type of IPS panel?

    Cant seem to find this info anywhere, it must not be important to anyone: maybe you can help. What type of IPS panel is the LG LM270WQ1? S-IPS, H-IPS, P-IPS? Classic Hitachi IPS?
    All of the teardowns from the last few years of these products simply say it is an IPS panel.
    Thanks for any help.
  6. Fat Fatster macrumors newbie

    Sep 3, 2010
    one1 ... thank you so much for the post.

    I have a Aug 2010 iMac. the LG panel has the


    designation. it has the little BLACK plughole.

    The screen of course has the usual problem:

    I very fortunately found a replacement screen for a low price, but the replacement screen is the


    designation with the little WHITE plug.

    I am going to just open the metal panel (two or three large X screws) to replace the board as you describe -- to be clear, that's what you mean right? I should pop off the largish metal panel, and then it's easy to swap the boards?

    I guess an alternate would be to CHANGE THE LITTLE CABLE - but goodness knows where you'd find such a thing?

    I'll just go ahed and try that anyway, but generally thanks a million for this fantastic post -- it makes one feel not alone in the world :)
  7. Fat Fatster, Mar 13, 2013
    Last edited: Mar 14, 2013

    Fat Fatster macrumors newbie

    Sep 3, 2010
    Yup, incredibly it worked perfectly! Thanks a million to one1.

    Here's two photos that show my original (ie newer) C2 (LM270WQ1)

    (BLACK plug type on the controller board)

    that comes from a Aug 2010, iMac quad 2.93 8go

    (Note that you can see this black plug (it has two tiny square holes on top) in image #3 at the bottom of this post. It is the "largest" object on the edge of the ControllerBoard right next to the camera.)

    And I bought from eBay an A2 (LM270WQ1)

    I bought it in 2013 (I am writing this in March 2013). one1 says that the A2 is from a Late 2009 iMac.

    (WHITE plug type on the controller board.)

    (Note the one from my iMac has the temperature sensor still attached. You just pull that off by sliding something l;ike a screwdriver underneath it, it is simply glued on.)

    [​IMG] [​IMG]

    These next large photos may help anyone who needs to swap the ControllerBoard.

    The long flap of metal (it is as wide as the whole display) easily lifts-up if you remove the four obvious screens.

    To open that type of ribbon cable. The long BLACK piece actaully lifts-up. In fact it lifts-up towards the INSIDE of the controller board. (Or the other way on the other end of the ribbon cables.) If you look carefully at the #3 photo below you will see the long BLACK things standing up.

    Very luckily for me, the ribbon cables worked the first time I put the ribbon cables in. Suggest, be very careful that the ribbon cables look really STRAIGHT. Using a magnifying glass, look at the left and right side of the ribbon cables and see if they are microscopically at the same distance against the plastic edges of the receiver. Note that they push in a little further on one side but there is some tiny something inside (you can't see) which they HIT on the other side. So it would be easy to incorrect push in both sides, meaning they would be on a slight angle. Do not do this. Slide in only until you feel the "stop" on the one side. Looking at the "posts" on each side, ensure the ribbon is absolutely square.

    Tip: using your old panel which you are probably throwing away, and the ControllerBoard you won't be using: You can experiment over and over seating the ribbon cables on that unneeded panel/board.

    [​IMG] [​IMG] [​IMG]

    I hope this helps someone and I can only thank One1 yet again, thank you One1. You saved me $1000 !!
  8. one1 thread starter macrumors 65816

    Jun 17, 2007
    Chattanooga, TN
    Hey that's great! Good job too! Back when this was posted in 2011 I was the first to actually put these two side by side and figure this out so I had to do it the hard way. Glad everything worked out for you!
  9. Fat Fatster macrumors newbie

    Sep 3, 2010
    I truly thank you so much! You literally saved me a grand and a huge amount of hassle. Thank you so much man, cheers.

    I now just turn that iMac on and off all day saying "Whoo, it works!" :)

    Thanks again, cheers

  10. DCWS6 macrumors newbie

    Aug 10, 2013
    Will I have to switch out the boards if I replace a 2011 21.5" iMac (model A1311) with a 2010 21.5" iMac (also model A1311) lcd panel? The macs have the same model number but the panels do not.

    2011 panel model #LM215WF3 (SD) (C2)

    2010 panel model #LM215WF3 (SD) (A1)

  11. dpgorman70 macrumors newbie

    Sep 9, 2013
    Hey man, I note that you had luck switching the LM270WQ1. I think you made this clear, but just to make sure, did you remove the full metal backing from the panel and switch out just the LCD?

    I appreciate any help. I have a 27" display and an 27" iMac. I want to put the 27" imac display in the 27" cinema display but the connections are slightly different. I'm guessing I just remove the back metal panel from the LCD and the iMac, and just swap the actual LCD, yes?

    Aplogies in advance for my lack of english skills at the moment. it's been a hell of a long day. thanks in advance for any help you can provide.

  12. dtjay7 macrumors regular

    Jul 25, 2008
    N. CA
    Thanks for posting this information. I have a 2011 and the backlight part was taken apart and damaged. Based on this thread I have analyzed the differences and plan to exchange the 2011 controller board onto a 2009 display. The cables, of course, will be from the 2011. I have purchased a 2009 display and I am just waiting for it to arrive. I am so excited to have a screen on my iMac. I could not see paying 600 for a display, when I could find one. Again, thank you very much.
  13. dtjay7 macrumors regular

    Jul 25, 2008
    N. CA
    Okay, I just wanted to let people know. I have taken the control card off of the 2011 display and placed it onto a 2009 display and used the cables for a 2011. I had to change the bracket from the 2011 to the 2009 on the left to clear something on the left side. But, it works great. I am so happy that I saved sooooo much by using a 2009 display with the 2011 controller. Thank you to the OP for the idea and knowledge.

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