Help! Replacement LCD not working in 20" iMac

Discussion in 'iMac' started by bertieuk, Jul 26, 2007.

  1. bertieuk macrumors newbie

    Jan 10, 2006
    After reading through posts here and elsewhere on the internet, I purchased a Dell 2007WFP 20" monitor to replace the cracked LCD in my 20" iMac CoreDuo.

    The panel is an LM201W01 as expected.

    The LCD works in the Dell housing but not in the iMac, it doesn't even light up. I connected a second monitor to the iMac and that works, but System Profiler states Display Not Connected for the internal LCD.

    I've checked and double checked the two power connections and the LVDS connection and are good and home. I even put the original cracked LCD back in and that works.

    I've reset PRAM, NVRAM numerous times, but nothing :-(

    Anyone any further ideas? Am starting to look a bit stupid to the boss...

  2. Angrist macrumors 6502

    Mar 11, 2005
    MI or NJ
    Break out a multi-meter and check that nothing is mis-marked ?

    Where did you find a how-to to replace the LCD btw?
  3. bertieuk thread starter macrumors newbie

    Jan 10, 2006
    There is quite a bit of info on these forums that the LM201W01 panel from the Dell 2007WFP is the same as the one in the iMac 20".

    And I used the general iMac disassembly guides on the net.

    The panel is a drop in replacement for the existing one, the power connections and the LVDS cable are in the exact same place.

    The strange thing is that my cracked panel works fine in the Dell housing :confused:

    I've found there is a small screw resistor (?) in the top right corner (through a hole) but this seems to turn and turn and turn and has no effect.

  4. ChristoRogers macrumors newbie

    Jul 28, 2007
    Tokyo, Japan
    Hey, can you provide me with the resources you found to do this? My roommate's 17" iMac's display has a worsening vertical line problem and needs to be replaced. The problem is Apple charges $600 for this repair, which is kind of absurd... so it would be awesome if I could fix this myself. Thanks.
  5. bertieuk thread starter macrumors newbie

    Jan 10, 2006
    Still not got it working...

    Coming to the conclusion that Apple modify the LCD panel in some way as to not make it directly replacable with a generic version.

    Therefore I'd not reccomend this route, look out for a faulty iMac to use just the LCD.

  6. GoCubsGo macrumors Nehalem


    Feb 19, 2005
    That is interesting. Any chance you can get your hands on an iMac LCD and make sure it's just the dell display? I think you may be right that there has got to be some modification to the display by Apple to prevent the use of Dell's (not specifically Dell's) but any 3rd party display.
  7. bertieuk thread starter macrumors newbie

    Jan 10, 2006
    The backup to my theory that this would work was that I had another iMac's lcd replaced under warranty. Apple replaced the Samsung panel with an LG panel (Apple part no. 661-3881)

    When you look up the LG panel (661-3881) in Google, it is the LM201W01 lcd, and the Apple panel even appears on the FCC report for the LM201W01!

    Still not working btw :-(

  8. simpi macrumors newbie

    Nov 3, 2007
    I saw this thread and I am very interested to know if you did get it working.
    It's a few months later since your last mail...
    You could exchange the screen in the machine that Apple fitted with same type of screen?

  9. AlexisV macrumors 68000


    Mar 12, 2007
    Manchester, UK
    Any photos? We might be able to help if we can see the setup.
  10. Leon Kowalski macrumors 6502a

    Leon Kowalski

    Sep 20, 2007
    Gondwanaland Reunification Front HQ
    Download an evaluation copy of SwitchResX and use it to dump the DDC info block from each display.

    System Preferences > SwitchResX > Export DDC

    Is anything different?

  11. bertieuk thread starter macrumors newbie

    Jan 10, 2006
    No, never got it to work.

    Bought a faulty G5 20" off ebay but that screen didn't work either.

    In the swap in/out my colleague managed to short the LCD to the intel 20" 's power supply, so took a bit of time to get a replacement.

    Then the G5 LCD blew the power supply in the Dell housing when I tested it in there, :(

    So a.t.m I have, 1 x Intel 20" with no LCD but works with second screen, 1 x G5 20" dead video GPU, 1 x Dell 20" dead power supply.

    BTW, I tried switchResX but not much help as the LCD panel isn't detected by the logic board.

    And I could post pics, but they would only be of the three screens and wouldn't be much help.

    I do have more 20" Intel iMac's but am reluctant to damage more that are used daily by colleagues.

  12. thetman macrumors member

    Dec 30, 2003
    It's been awhile since the last post but I came across this thread in google while trying to accomplish the same thing - replace the 20" lcd for cheaper than apple prices.

    I noticed your username indicates you might be from the uk. Is it possible that the panel does not work because the Dell screen is from a country that uses a different voltage? I'm not trying to be rude just asking because I dont know that much about internal parts of an LCD.


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