Imac keyboard Power button - won't work to boot, but will in OS X??? Help?

Discussion in 'Macintosh Computers' started by ran, Jun 12, 2004.

  1. ran macrumors newbie

    Jan 13, 2004
    Hi everyone!

    Well, here's the story:

    Scrounged: iMac 350mhz slot-loader (indigo)
    Scrounged: Imac keyboard

    This thing was missing some bits and pieces (e.g. HD, mem, PRAM battery, some case parts, etc...)

    I scrounged all that up, put it together, and found that pushing the power button on the Imac itself seems to work just fine. Unfortunately, I'm missing the "inner button" part of the power button, so, when the case plastics are put together, I can not use that power button.

    So, I thought, aha! I'd just use the power button on the keyboard.

    Well, I find that pushing that button will *not* power up the computer. However, if I start the computer with the power button on the computer itself (have to pull off bottom case plastics), then I find that OS X is responsive to the keyboard's power button by prompting for, 'Shutdown, Sleep, or Restart'.

    So, that means the button works, right?? Well, if so, then why not to start up the computer???
    (everything else on the keyboard seems fine)

    I've tried removing/reinstalling the PRAM batter, resetting the PMU (by pushing that little buttonpad on the logic board for 30seconds)..but all to no avail.

    *WHY* would the keyboard's power button *only* work after the computer is started but not to start it up??? :confused:

  2. reaper macrumors 6502

    Apr 9, 2004
    19th Hole
    I don't believe thata OS X supports that functionality. It uses the "power" button for the sleep and shotdown dialog once the computer is on, but I don't believe it will turn on the computer as it would have in OS 9 or earlier.

    - reaper
  3. ran thread starter macrumors newbie

    Jan 13, 2004
    Hi reaper and thanks for the reply...

    What I meant by that was that there was no physical problem with the button - the computer can recognize when the button is why can't the computer recognize it when it is off?

    As an addendum, I've also tried the following:

    Put in a new PRAM battery (checked voltage, reads ~3.54)

    Reset NVRAM by doing the following in Open Firmware:
    (the last ended with an automatic chime/reboot)

    This still hasn't solved the problem. I know others have seen it, as reference on this webpage...but so far haven't found a solution..

    anyone else? :cool:
  4. ran thread starter macrumors newbie

    Jan 13, 2004
    oh..wait a minute...are you saying that power on by keyboard just isn't supported if the boot system is OS X? In other words, if I switch it back to OS should work?
  5. ran thread starter macrumors newbie

    Jan 13, 2004
    OK, I just confirmed at work that an IMac running OS X 10.2.x will powerup just fine from a keyboard power that's not it... :cool:

    Any other ideas?

    Could the firmware be "partially corrupted" or something like that?

  6. whooleytoo macrumors 603


    Aug 2, 2002
    Cork, Ireland.
    I believe Apple are removing this functionality (the Power button is already removed from new Apple keyboards) due to an issue where powered USB devices could cause your Mac to spontaneously boot up.

    I don't know how precisely it's being disabled (i.e. is it the OS, or firmware that's changed to disable the power button).
  7. osprey76 macrumors 6502

    May 3, 2004
    Oklahoma City, OK
    That makes sense to me. I know changing USB configurations will often wake the computer if in deep sleep.

    I've also read that Apple removed the power button because if the keyboard was connected through a hub the power button would not always make the computer boot. So, are you running the keyboard through hub at all?

    My mom has a Sawtooth G4 running 10.3 and as far as I remember the power key was working fine last time I was home. My memory is a bit hazy since that was some months ago.
  8. Hemingray macrumors 68030


    Jan 9, 2002
    Ha ha haaa!
    The iMac keyboard's power button should definitely boot the iMac, I would think that functionality should be independent from the system. Is the keyboard the same one that came with the Indigo? If it's a different one, it's possible that maybe it's somehow not compatible with the computer. (Recently I tried plugging a Rev.B iMac's keyboard into a Rev.A iMac and it went totally wacky. Not sure if it was a compatibility problem or a bad keyboard, but the keyboard was working fine not six months prior.) That's all I can think of...
  9. osprey76 macrumors 6502

    May 3, 2004
    Oklahoma City, OK
    As I think about it, I agree more and more with you. Even if Apple has discontinued the power key and the ability of the computer to boot from a USB trigger, I don't see how they could turn this off in older computers. Firmware doesn't load until after the computer is booting up. The system software has no bearing on the most basic level of turning on the power. Though, it's interesting how the splash screen soon after power on is OS 9 (gray) or OS 10 (white) dependent.
  10. ran thread starter macrumors newbie

    Jan 13, 2004
    Thanks for the replies, everyone...

    1. The keyboard is definitely *not* the one that came with the computer. Everything is scrounged/second-hand.

    2. The keyboard is directly plugged into the side of the IMac.

    3. Ummmmmm....well, that's where I am.

    A question: Is it possible for the firmware to be partially "corrupt"?

    That is, would reinstalling the 4.1.9 firmware possibly fix this? If so, how does one *RE*-install the firmware? Doesn't the updater check the current firmware and refuse to install if it's the same?


    Note: A kind person is sending me the inner power button for the I'll be able to use that...but I *would* like to solve this issue.... :cool:

  11. ran thread starter macrumors newbie

    Jan 13, 2004

    an update:

    I've tested the keyboard at two macs at work, a G4 tower and an Imac..the keyboard works *FINE* powering up those two, it is definitely an issue with the Imac.

    What do people think about the "firmware" issue mentioned above....could this be a culprit?

    Is there a way to force the firmware to "reinstall"?

  12. Finiksa macrumors 6502a


    Feb 23, 2003
    I doubt it's the result of corrupt firmware. I have a G3 iMac and a spare keyboard with power button. If I recall correctly mine doesn't turn on via the keyboard, I'll connect it up later today and try again.

    Did your iMac come with the Pro keyboard or button style keyboard when originally sold by Apple? Perhaps Apple just disabled support for this in newer models that didn't ship with the older keyboard.

    I'm not really sure I haven't given it much thought before, but I think this is normal behavior.

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