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Imac G3 (1998) Screen Problem

1282 Views 8 Replies Latest reply: Dec 6, 2012 1:07 PM by Windowssonic RSS
Windowssonic Calculating status...
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Mar 4, 2012 11:44 AM

I Bought a Imac g3 (1998) Orange at a thrift store yesterday and it has been having Screen Flicker problems. The first day I used this computer it was working fine, until the next day when the screen (Keep in mind i was using it) started to flicker at about a hour of usage. I unpluged the system, and then unpluged everything else. I readed other messages and one said it might interfear with the cables, and to turn down the sound. I could not turn down the sound beacuse the IMac could not let me. I was running the system with extentions OFF, beacuse the system was missing a Itunes MPEG extention, so thats why. Thank you if you could help me. Can you maybe tell me where to get the itunes Mac OS 8 MPEG extention, too?

IMac G3 (Original) , Mac OS 8.6 or Earlier, No other details
  • rccharles Level 5 Level 5 (5,115 points)
    Currently Being Moderated
    Mar 4, 2012 8:13 PM (in response to Windowssonic)

    All of the iMac g3's have screen problems.  It was the era of bad capacitors. The iMac g3 models a,b,c, & d had an internal fan.  Verify that it is working.  The repair of CRT's is a lost art.


    The problem could be heat related. You could try increasing the air flow. Try putting a fan below & direct the airflow up.


    You could look on ebay for Mac OS 9.x.  Make sure you get the full install version .  A large gold 9 on the cd & box.


    You might want to look for another cheap machine.  You would be better off with a newer machine.  Look for a mac mini.


    I readed other messages and one said it might interfear with the cables,


    I would think that this would show up when you started the machine & not after it ran for awhile.


    I recall that placing headphone in the head phone jack turns off the speaker sound.  I think that a dummy jack turns off speaker sound too.



  • rccharles Level 5 Level 5 (5,115 points)
    Currently Being Moderated
    Mar 5, 2012 10:26 AM (in response to Windowssonic)

    iMac g3

    a -- 233 2mg vram

    b -- 233 6mg vram

    c -- 266

    d -- 333


    Query by serial number

    "A serial number is a unique, identifying number or group of numbers and letters assigned to an individual piece of hardware or software. It's used for various things depending on the product / brand but what is your Mac's serial number for and more importantly... what is it hiding and what can it do for you ?"



       ( hint by K Shaffer  )


    I think that you have a capacitor problem.  The power off sound is an indicator.


    You could try cooling your iMac some more. 


    How to fix iMac capactor problem.




    What are you wanting to accomplish  with this machine?  Is it a hobby machine?


    I'd recommend at least a G4 processor & 1ghz.  Most people would say an early intel processor Mac.



  • Mac Man JW Level 2 Level 2 (170 points)
    Currently Being Moderated
    Mar 9, 2012 8:57 PM (in response to Windowssonic)

    That sound is a bad flyback transformer the flyback transformer is what makes the hi voltage for the monitor to work and would make the screen flicker if it is going bad. I just got 5 of the tray loading imacs that have this issue if yours makes a hissing nose when off i am %100 sure it is the flyback transformer

  • Mac Man JW Level 2 Level 2 (170 points)
    Currently Being Moderated
    Oct 8, 2012 6:43 PM (in response to Windowssonic)

    I think this is the right Flyback You will have to open it up and cheek the #'s on the flyback. This persion from this thread (post # 18) ordered one for his imac and it worked ok! but remember CRT's can hold Power even when off so make sure you know what you are doing before you open it


    Ebay Link to flyback transformer DME:X:RTQ:US:1123


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