Help! imac G4 screen almost black...

Discussion in 'Mac Basics and Help' started by faithfulFrank, Sep 13, 2006.

  1. faithfulFrank macrumors member

    Dec 31, 2003
    Central Florida
    Hi all,
    I'm at work now but my son called me and told me, "Mom was on the computer and all of a sudden she said that the screen like died"..........
    He checked it, and he said you can barely see the computer is working but the screen is not lit. He said it is so dark you sometimes lose where the mouse cursor is, and you can barely see the dock, etc. He said he was barely able to get to the brightness settings and tried to adjust....he said he turned it up all the way but it did not do anything.

    My G4 17" imac is almost 4 years old........I really cannot afford a new one easily. The good news is that he says you can barely see everything still, so the computer itself is is a screen problem.

    Here are my dumb questions........(I love my macs, but am a novice)....

    1) is there a way to temporarily hook up another monitor to it, like you can with my son's powerbook? (he is away at college, so the G4 is all I have right now)

    2) could this just be a software problem, or could it come back after it cools, etc?

    3) Could I just buy a new LCD screen, like off ebay, either another 17" or maybe "upgrade" to a 20" ?

    4) would fixing it be worth it? I would think it is just a couple of wires into that half a volleyball bottom....I hope?

    Luckily, I just bought a used powerbook for this son off ebay, and it should be delivered tomorrow, so hopefully I'll have SOMETHING. Is 4 years the norm for a mac? I really like my good old g4..........

    Thank you in advance for any help.....

    Frank D.
  2. Old Smuggler macrumors 6502a

    Old Smuggler

    Sep 8, 2006
    wow frank I wish the best for you
    its possible it could be a software problem
    i have a treo 650 phone and i installed some software on it mOcean it was called well it killed the screen same symptoms as you nothing i could barely see anything
    i did a hard reset to original software and it fixed it
    so maybe a erase and install may fix your system
    two totaly different products but both have an OS and LCD so its a shot

    stick around and see what the more experienced G4 iMac owners have to say
  3. Jiddick ExRex macrumors 65816

    Jiddick ExRex

    May 14, 2006
    Roskilde, DK
    Is it constantly darkened or does it only happen in intervals?

    My G4 iBook is acting the same way, but that's because I installed Screen Spanning Doctor which is the culprit.
  4. e²Studios macrumors 68020


    Apr 12, 2005
    Could it be that the backlight is going out? if you can see an image in bright ambient light then maybe the backlight is out, or maybe a cable has gotten pinched between the hinge and the display/logic board.

    Sorry if that doesnt really help, but just brain dump on what i thought it could be

  5. the kid 05 macrumors regular

    Aug 11, 2006
    St. Charles Illinois (subdiv of Chi-town)
    on my friends ibook there is a cmd+ f1 and f2 to lighten and darken maybe she acciedn't hit that?
  6. Old Smuggler macrumors 6502a

    Old Smuggler

    Sep 8, 2006
    did you try apple hardware test pram reset and erase and install yet
    you will never know until you do if its a hardware problem like a backlight

    edit: i meant erase and install
  7. Kingsly macrumors 68040


    hit F15 repeatedly, though it sounds like the backlight died.

    Sell it on eBay and get a MacMini.
  8. iMeowbot macrumors G3


    Aug 30, 2003
    Yeah, there is a mini VGA port on those. You can get the cable from Apple. Search the Apple store for M8639, it's 20 bucks, same as in town.
    Unlikely. It could be the fluorescent tubes, inverter, or logic board. Just for grins, you can try resetting the PMU, but I don't think it will help.
    The only display that's going to fit on the top of your iMac is one from another iMac of the same model. Some people behead their lamps and leave the dome hooked up to an external monitor, kind of like a round mini.

    The best mod I've seen yet involved a wooden dowel where the chrome neck used to be, and the base painted red, so the whole thing looked like a giant toilet plunger.
    There are quite a few wires, because along with the display and lighting, you have the microphone and sleep light. It's a pain to disassemble (you kind of have to start at the bottom and work your way up). You could always leave the dead screen there and not use it.

    There are parts around, if you want to try to fix it, but you do have the challenge of figuring out what part broke.
  9. EHUnlucky7x9@ao macrumors 6502

    Jan 8, 2006
    New Jersey
    Cheapest solution is purchasing the mini-VGA adapter and hooking it up to an external monitor.

    Next best thing is to purchase a $150 LCD replacement. All it is just the torx screws located behind the LCD panel. Just gotta make sure you do it carefully.

    The moneysaver is to either purchase a Mac Mini (intel solo would be future safe for a while) and transfer your data and sell the iMac for what its worth. Probably around $200-$300 at most.
  10. rshart5 macrumors newbie

    Oct 31, 2006
    Fixing iMac black screen problems

    The problem when an Imac LCD screen goes black (but you can faintly see the screen especially if you shine a flashlight on the screen) is you have lost the back light. This is NOT a logic board problem (many shops will tell you it is and want to replace the board - $500) and changing the board will not solve your problem. The loss of the back light is caused by a failed invertert in the screen itself. This is an $80 part and takes 20 minutes to replace (yourself). You can order a new inverter through We Love Macs (I am NOT associated with them but I did buy my replacement from them) or others.
  11. faithfulFrank thread starter macrumors member

    Dec 31, 2003
    Central Florida
    Thank you all.
    I've researched this some, and was told that these screens have two lights in them, so the chance of it being a bulb is very low. Usually, like 100% of the time, it is an inverter board, which actually looks like a small stick with a few wires.
    The apple store wanted about $300 to fix it. I was able to buy a new inverter board for $70.00, and my local mac guru installed it overnight for $50. It is now working great and I am very happy.

    Frank D.
  12. surabaya7 macrumors newbie

    Nov 28, 2006
    Help! Imac g4 screen almost black

    EHUnlucky7x9@ao - I just bought the g4 LG Phillips'
    LCD to replace my cracked original. How do I install it?
  13. cellprof macrumors newbie

    Dec 5, 2006
    Top half of the 20" flat-panel screen on my iMac G4 1.25 suddenly went black, and now the rest of the screen is sometimes blurry. As I like its features, and my apps and data are on it, I'd like to save it, either by replacing the screen or by taking the neck and screen off and connecting an external display. The price from Apple to replace the display is silly.

    Either 1) I find a replacement that fits on the neck, 2) remove the neck and run a cable from its graphics card to a screen (don't know how, of course), or 3) remove the neck and run an external display through the VGA connector on the base. Hope for a neat-looking solution- any experienced Macgeeks out there who can point us in the right direction? thanks in advance for your knowledge!
  14. mklos macrumors 68000


    Dec 4, 2002
    My house!
    I guarantee you its the LCD Inverter. A couple of weeks ago I just replaced it on my dad's 1 GHz 17" iMac G4 for the same reason. We do the same thing where I work all the time for people's notebooks and it fixes the issue every time. As long as the screen isn't cracked, all you need is the inverter.

    I got mine from for around $85. A new screen will NOT fix your issue unless it just happens to come with a new inverter which most won't. Usually all you'll get is the LCD panel itself with no bezel, cables, inverter, etc.

    Changing the inverter isn't too bad. Just be VERY careful with the panel. Don't flex it too much or it will crack. There's 3 tiny hex screws under the display that hold it in place. Then push the bottom upward I think it is and the display will come apart. Be careful of the wires inside the panel. Apple leaves JUST enough cable to go from the neck to the display so everything is pretty tight. You'll probably have to undo those cables.
  15. meisterbreaker macrumors newbie

    Dec 9, 2006
    inverter board

    My G4 monitor went gray a while back too.
    I was told it was the arm or logic board and it just wasn't worth paying to fix it.
    So I just slapped on an external monitor and have been using it instead.
    However, if an inverter board is so cheap I'm tempted to get one and try it.

    My screen is gray and I can still control the brightness from the display settings. However, I don't have an "Arrangement" tab in the display settings. With an external monitor, shouldn't that become active?
    Since i don't see Arrangement I sorta assumed that it was the logic board. It seems the os no longer sees the built in monitor.
    It still has a display settings dialog, but when I change the iMac's display settings it just overrides and changes my external monitors settings. Like it thinks the external is the iMac built in monitor.

    Does anyone think an inverter board could bring back my built in monitor?

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