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  1. #1

    Member Since
    Nov 05, 2011
    imac G4 800Mhz
    imac power testing
    Returned from holiday during which there had been at least one power cut. My old iMac G4 17" 800Mhz would not boot at all (nothing).

    So, checked online and replaced the internal battery. Still nothing.

    Looking at the service manual (page 117) there seems to be a helpful way to test the various voltages (battery, 12v and main); nice description and image.

    BUT, my iMac does not have the voltage test points shown or anything remotely like them that I can see.

    1. Has anyone else had this problem?
    2. How else should I test the power supply (i'm assuming that power is the problem)

    I am an electical engineer so quite happy digging about inside!

    Thanks in advance

  2. #2

    Member Since
    Jun 07, 2006
    Late 2015 27" iMac, 3.3ghz, M395 gpu, 2tb Fusion, 8gb
    Nothing at all? Check the fuse? Is there a fuse? Must be. If you open it up you should be able to trace the PS to the motherboard. I'd assume there is some kind of switching PS in there so check the output from that. Since you're an EE I shouldn't have to warn you about safety.

  3. #3

    Member Since
    Nov 05, 2011
    imac G4 800Mhz
    Where would the fuse be?
    Can't see any sensible fuse loaction inside the Mac. The power supply fuse is fine.

    I was hoping for some guidance as to where the helpful power test points indicated in the service user manual had been moved to!

    I really don't want to further dismantle the insides (remove drives etc) as i can tell its going to be a ***** to get back afterwards!


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