Unibody LCD replacement stays blank

Discussion in 'MacBook' started by Endeer, Aug 8, 2009.

  1. Endeer macrumors newbie

    Joined:
    Jun 28, 2009
    #1
    Hello everyone,

    I have cracked the LCD on my 13" MacBook Unibody (Late 2008) and for reasons took the self-service way.

    First thing I have noticed after removing the LCD was that ioreg's EDID data reported I had LP133WX2-TLC1, but on the actual panel there was LP133WX2-TLC2 sticker. Unaware of this (and actually I have no way of telling which one it really is), I ordered the former from ScreenCountry.com, installed it and was greeted with no image, no backlight. Putting back the original cracked LCD, the backlight works, and that's about as much as the LCD can do now.

    So I put in the new one again, and tried resetting PRAM, NVRAM, SMC, tried booting from install DVD, which resets about 15 seconds after it starts loading. I have no miniDisplayPort-anything cable, so I used voiceover to activate ssh access, and ioreg reported no display there. I also enabled VNC and even in GUI there was said that no screen was attached. The panel never even lit up, the connectors stayed cool.

    Well, I'm negotiating replacement panel with ScreenCountry, but wanted to ask whether anyone here doesn't see any other option.

    Thanks for reading.
     
  2. Endeer thread starter macrumors newbie

    Joined:
    Jun 28, 2009
    #2
    Just in case this helps someone in the future.

    I have later ordered one another display, from a different place, this time LP133WX2-TLC2, the seller told me I need this one after describing my LP133WX2-TLC1 vs. LP133WX2-TLC2 problem. The LCD arrived, and guess what, stayed black/blank, no backlight. But! When I used ioreg, the display was listed there. When everything works properly, it's EDID should be there twice, but there was only once. I have checked the EDID - it had Apple as vendor and proper ID in it (LP133WX2-TLC2), but - wrong checksum. The seller told me another of his customers has this problem too, that he must've received bad batch, and that he takes it back at his cost.

    Still, I didn't want to give so easily, I heard it was possible to change EDID using software only - from Windows, using paid version of PowerStrip. First surprise came that after (blindly) selecting BootCamped Windows for booting, the display enabled backlight, even though it otherwise stayed grey/black (cannot tell). Then I really managed to change the EDID - I tried both just fixing the checksum and using the original display's EDID with LP133WX2-TLC1 identification. The EDID modification brought me backlight even when MacOS was booted and I could control it's brightness using the usual keys.

    But still no image - it was dark grey/black. Ioreg now reports there's proper Apple display detected, but all I see is me (reflecting on the screen). I was trying and trying, but eventually gave up and returned the panel. Then I hit quite a deal on eBay, like-new top display assembly, complete, original, with one minor scratch on side (in the aluminium).

    When the assembly arrived, I connected it... and for the first time since cracking the display, I saw an apple. In happy state I decided to screw it a little together, so I don't have to hold the base and top while trying to boot, powered it up again... and received the same grey/black screen with backlight as with the previous panel. That was depressive. I tried for a while, but couldn't do anything about it. Eventually I tried connecting the old broken screen - it appeared to show some random lines - and then back the new one - and to my surprise, the image came back, and booted.

    After a few shutdowns/power ups, the image turned grey again. I had some theories what was the cause of turning grey/black, but to this day I haven't managed to trigger the problem again - the trick with reconnecting the broken panel worked, and now it's been running flawless for many days. I have no idea what caused the screen to turn grey and stay that way until the system got back the old panel.

    I guess it wanted to say goodbye.
     
  3. Endeer thread starter macrumors newbie

    Joined:
    Jun 28, 2009
    #3
    And finally, the conclusion.

    Backlight with no image was caused by bad contact at the connection point between display cable and system board. Learned that light pressure on the connector during startup helped getting image (after startup, the pressure was no longer needed). Tried sticking some cloth on top of the connector (system board side, "female"), so that when bottom case was in place, it would create the needed pressure, but it only helped for some time.

    Eventually tried adding two or three layers of transparent adhesive foil to the bottom side of connector (cable side, "male"). This created pressure right inside the connector (female) and everything is working fine ever since.
     
  4. l.a.rossmann macrumors 65816

    l.a.rossmann

    Joined:
    May 15, 2009
    Location:
    Brooklyn
    #4
    screencountry panels often suck. I recommend cbohk or luna commerce for those ones, the latter being pricier but speedier.

    a) The number doesn't matter, the letter does.

    An LP154WP2-TLA1, TLA2, TLA3, TLA4 are all compatible. An LP154WP2-TLC1 is not compatible with a TLA1. This is a regular LG Philips thing. Sometimes the letters can be different in the end, such as the LP133WX1-TLN3, LP133WX1-TLA1, LP133WX1-TLC1, and they'll be compatible. But the numbers never matter at the end and have no effects on compatibility.

    Also, the revision # is rarely updated on the PCB. It's updated on the sticker.

    b) This isn't like the old machines. There is no slack on the cable. It is very easy to not reinsert it properly or to damage the connector on reinsertion. There is a little bracket piece that holds the connector on that has to be in place. When pushing the connector up into the screen, don't use any tool that could damage the cable. A common problem is using too much pressure to try and jam the cable up into the screen and ripping it off the logic bord.

    c) For the same price of the LP133WX1-TLC*, you could've gotten a B133EW07, a nice upgrade. :(
     
  5. Endeer thread starter macrumors newbie

    Joined:
    Jun 28, 2009
    #5
    I have actually been quite careful about the cable, and knew about the bracket to lock, but still it worked rather intermittently. Seems that the problem was possibly only on the pins used for display identification, as after the computer initialized, the image never disappeared.

    As for the price of LP133 - don't forget it was actually a year ago, and unfortunately I had no idea where to look for the good deals (and getting them shipped to the Czech Republic...). Even if I had found the sites you mention (cbohk, luna), I would have dismissed them thinking they wouldn't have wanted to hear about ordering one panel.

    I'm just a programmer, who once replaced screen in friend's notebook (HP, authorized service quoted $1000, got the panel from eBay for $120 or something like that) and now everyone thinks I can do it with any laptop (the MacBook wasn't mine either, but it would be a hassle to talk about it that way).

    Hopefully your advice on sites will be helpful to someone in the future. And also thanks for the compatibility information.
     

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