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  1. #1

    Member Since
    Apr 30, 2009
    iMac G3 won't power up

    I have 2 iMac G3's that I rescued before they were to be trashed. I don't know a whole lot about Mac's. One is blue and one is red.

    I know the red one is better then the blue.

    I hadn't used the red one in a few months and now it has no lights on it. The power is good, I verified on the blue one. When I plug it in I hear that electronics expanding sound but nothing working inside and I have no lights on it.

    I googled around and opened the back and took out the battery, hit that reset button next to the ram and still nothing.

    Any ideas? Power supply? If it's the power supply, what do I buy? Could I just steal from the blue one?


  2. #2

    Member Since
    Apr 30, 2009
    I dont mean to be rude but you can buy a complete g3 iMac on ebay for less then $10.00.

    Apple M4984 iMac G3/333 Lime iMac PowerMac NR - eBay (item 320363986720 end time May-01-09 12:20:38 PDT)

    I wouldnt waste my time if I were you. Sorry I dont have a better answer.

    Good luck!

  3. #3

    hughvane's Avatar
    Member Since
    May 18, 2008
    Amberley, Canterbury, New Zealand
    MacMini 4.1, OS 10.11 and 10.6; Macbook Pro 8.2, OS 10.12, MacBook 4.1, OS 10.6.8
    Good on you tp for having a go at fixing. If you hear "electronics expanding" sound, then the power supply is probably okay. It could be faulty RAM or a failed hard drive. That's a pretty old Mac.

    Smmuck is right about the pure economics of the situation, but if, like me, you hate to see something working (or nearly so) going to waste, I'd suggest that you cannibalise the blue one for parts to make the red one work. You could also follow Smmuck's (unintended?) idea and buy a cheap working one for parts alone.

    Look thoroughly on both iMacs for the model numbers so we can determine which era of iMac they came from (probably the '5-flavor' range). A good guide for dealing with older Macs comes from Mactracker, and there are plenty of video instruction clips on sites like YouTube about taking them apart.

  4. #4

    Member Since
    Apr 24, 2009
    MacBook Pro 15" 2.8 GHz
    If the 'blue' one is a bondi blue tray loading iMac, they have some well documented common problems. One is that when powered on, you hear a crackle from the EHT for the CRT, then it shuts off. This is usually caused by the flyback transformer failing on the analog board. A capacitor within the transformer opens causing the EHT to rise to high, and safety circuitry shuts it down until it's been left off for some time. This can normally be verified by unscrewing and pulling off the bottom plate, then removing the 15 pin 'D' connector monitor lead. If it then powers up but with no screen brightness that's the problem. The logic behind this test is removing the plug disconnects the H & V syncs, operating the power saving thus shutting off the voltage supply to the defective area of the analog board. The simple fix is then to add an external monitor, often by using a mac adapter. A proper fix isn't economically viable, plus Apple themselves no longer supply parts for G3 iMac's, they are vintage.

    It could be other things, but that was one of the most common problems before users just started dumping them.

    More info on the models is required.

  5. #5

    louishen's Avatar
    Member Since
    Oct 22, 2007
    Mac Mini Core i7 2012 | White 2009 MacBook 2 Ghz | 733 Mhz G4 Quicksilver
    Have you tried putting the blue's battery in the red, dud lithium batteries can often cause start-up issues
    Member of the Month September 2008 & August 2012 | Found advice useful? use the rep system

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