g4 turns itself off /shuts down unexpectedly

Discussion in 'PowerPC Macs' started by juhlster1021, Sep 23, 2008.

  1. juhlster1021 macrumors newbie

    Jun 11, 2007
    Help! I've a MDD G4 dual 1.0 along with the wide acrylic-bezel 20" Mac monitor with the light in the lower right corner.

    Yep, it's starting to look ancient. But I still have much use for it EXCEPT that it has a very nasty habit of turning itself off catastropically in mid-thought, as it were.

    Oddly, this behavior comes and goes in spurts. it will hit hard for a couple of weeks then a couple of months will pass with relative peace and stability. Then, back to the crisis.

    Sometimes I get a warning from that power-on light in the bezel -- it might flash brighter for an instant, then within a few seconds the whole system loses power just as if I'd turned off my power strip. Other times, it pops in and out of sleep mode for several cycles, but usually this ends the same, with no power at all.

    Odder still, the machine has a tendency to turn itself on unaided. This can happen even after a controlled shutdown. It turns on, acts normal for 20 minutes, then maybe goes to sleep and wakes up a couple of times, then crashes. No intervention at all on my part at any time.

    This is not a software shutdown of any controlled variety.

    Anyone know what's happening? I can't tell you how much gnashing my teeth have endured. Thanks for any ideas or advice.
  2. juhlster1021 thread starter macrumors newbie

    Jun 11, 2007

    Still happening. Can't decide if it's an overheating issue or an issue with the monitor (ADC connection)...... Any help?
  3. California macrumors 68040


    Aug 21, 2004
    Sounds like a powersupply issue.

    Have you done a thorough cleaning of the insides? I've heard that dust build up is atrocious and this can affect the electronics. Tons of dust can cause heat build up which might be turning the machine on and off.
  4. CubeHacker macrumors 65816


    Apr 22, 2003
    You know, reading this, I thought to myself that it does kind of sound like the power supply going bad. Then it dawned on me - I know EXACTLY what this problem is. Because I had the same problem.

    What you are experiencing is the proximity sensitive power button on the ADC monitor going haywire. I had the same issue with the proximity sensitive button on the G4 Cube. It makes perfect sense:

    1.) If the computer is off, it turns itself on (button press)
    2.) If the computer is on, it goes to sleep (brief button press)
    3.) If the computer is on, it turns off (long button press)

    What really gave it away was how you mentioned you see the light on power button for the ADC monitor glow brighter for a moment before your computer would turn off. That the button pressing itself! My Cube did the same exact thing.

    As for how to fix it... thats more complicated. On my Cube, I took it apart, washed out the gasket around the power button and gave it a good cleaning. Once reinstalled, the problem was gone. I'm not sure how easy it is to take apart the ADC cinema displays to get to the power button. You might want to check online for dis assembly instructions.

    Note: Is the power button on the G4 tower itself also proximity sensitive? If the problem isn't on the ADC, then its on the tower. I don't know what the power buttons on the MDD look like.
  5. juhlster1021 thread starter macrumors newbie

    Jun 11, 2007
    Have had similar hunches

    I went so far to buy a(nother) used power supply. (Thanks to apple's unique PS design, new ones are $300 and I just don't love this mac that much, esp. on a hunch about an intermittent problem.....)

    So either both PSs are slightly but not catastrophically bad... or maybe it's that ADC monitor.

    Here's the thing, it seems like heat may be part of the equation... works for several hours, maybe, then it suddenly has a series of on/off episodes until it gives up altogether. Could that point to graphics card? Or?

    Anyone have graphics card problems that could show up this way?

    Guess I'll start with replacing the Apple montor a crap generic spare, and if that doesn't help I'll look for a replacement graphics card.


    BTW the tower switch is just a fancy push button. No magic proximity sensing. Thank goodness. Wish the monitor were the same.
  6. lannister80 macrumors 6502


    Apr 7, 2009
    I think it's the proximity sensor on your monitor. BUT, if you do want to get a new MDD power supply, there may be folks out there with a spare because they got the PS replaced due to the "windtunnel" issue with the early MDDs.

    My Dad had his original PS in a box somewhere, as it only ran for a few months before Apple shipped him a replacement. The replacement PS went bad after several years of running 24/7, so he popped the old "windtunnel" one back in. It's slightly louder than the old one, but not much, and it's practically brand-new.

    Just a thought, maybe someone on MacRumors has one available...
  7. juhlster1021 thread starter macrumors newbie

    Jun 11, 2007
    Thanks for the tip.

    The "wind tunnel" nickname is very well-earned, I can assure you.
  8. zmttoxics macrumors 65816


    May 20, 2008
    Power supply does seem likely, however...

    Two other things to check:
    -Reset your OBP. I work with Sun SPARC machines (OBP controlled too) and recently ran into something neat where bad power saving settings will cause them to randomly shut off.
    -Do a hardware check. The system could be panicing from a cpu fault or something of the like (usually these cause reboots, but you never know). There could also be a short some where in side like a screw touching the motherboard, or a pci slot cover came loose.

    Good Luck!
  9. awmazz macrumors 65816

    Jul 4, 2007
    I had this same problem on a MDD dual 1.25. Tried the PSU, the switch, the battery and everything else first out of a second MDD because I didn't want it to be the motherboard.

    It was the motherboard.

    Bought one off ebay and it's back to working perfectly again.

    Be sure to get the exact same model motherboard as yours. The 867MHz mobo is a slower bus speed and the dual 1.25 mobo may or may not work on your dual 1.0 (ie only one processor may show up, etc). The model number is written on the board just under where the modem card sits.
  10. awmazz macrumors 65816

    Jul 4, 2007
    PS. Your first post was Sept last year and you've put up with the intermittent shutdowns for 6 months? You're a very patient person!
  11. juhlster1021 thread starter macrumors newbie

    Jun 11, 2007
    Noooo, not the mobo. But then again.

    I did get and install a used power supply. Same results so either both have the same flaw or it's something else.

    I am either patient, or undercapitialzed, or stupid. I'll let my wife decide.

    Right now the G4 is sort of the "extra" computer that's overwhelmingly everyone's favorite choice. Got a really pretty nice Dell that works perfectly but we all keep using this one.

    And it's just intermittent enough to allow one to turn it on with a hint of optimism that "maybe it will not die mid-post today."

    Thanks all.
  12. juhlster1021 thread starter macrumors newbie

    Jun 11, 2007
    P.S. Re Mobo switch:

    <display ignorance>

    Does a used mobo come without CPUs then, and I would reuse my 1.0s? Could I buy a 1.25 or 1.42 mobo and the correct CPUs and upgrade the machine?

    </display ignorance>
  13. awmazz macrumors 65816

    Jul 4, 2007
    Motherboards are usually sold separately to CPUs on ebay once they strip a a machine so you'd have to buy both separately if you wanted to 'upgrade' so make sure they match each other. Probably for the same cost of both for this sort of exercise, you'd probably be able to pick up a complete G4 of the type you want for the same price or less anyway.

    It's actually pretty straightforward to undo all the screws and plugs to swap them out. I just googled to find the instructions. You'll just need to buy some Arctic Silver for when you reattach the CPU to the new mobo.
  14. CubeHacker macrumors 65816


    Apr 22, 2003
    I personally think you'd be wasting your time and money changing the motherboard. Have you tried hooking up a different display (say, the one from the dell) to the G4 to see if the shutdowns stop?
  15. MacLovergr8 macrumors newbie

    May 9, 2009
    I've Got The Same Problem

    Just inherited an old Power Mac G4, set it up and now I'm having the same problem. If I just wave my hand within 3 inches of the power button on the ADC monitor I can turn the machine on and off. (I knew I had a magnetic personality, but this is ridiculous!)

    Apparently, this computer was not doing this until it was moved to my house. How would the move have effected the power switch on the monitor?

    I tried covering the switch with dark paper in case it was light sensitive, that didn't work. The issues seems to be electromagnetic fields. I'm going to move the monitor farther away from the TV and see if that changes things.

    Do any of you smart folks have any other ideas how I can fix this? Is a new monitor the only solution? (Or, keep my body away from that silly switch on the monitor?)

  16. awmazz macrumors 65816

    Jul 4, 2007
    In the Displays Preferences panel, click the 'Options' option and then check 'Disable Power Button'.

    PS. Apart from the usual way, you can access the Display Preferences by touching the button on the opposite side of the screen. You can also disable this button the same way.

    EDIT: It may be the graphics card causing the power button glitch. Try re-seating it (pull it out and slot it back in again) in case it got knocked about during the move.
  17. MacLovergr8 macrumors newbie

    May 9, 2009
    Thank you But Still Need Help

    Hi Awmazz,

    This particular G4 is currently running OS 10.3.9. When I went into the Display Preferences there was no Options button to select.

    Also, FYI, the monitor button on the left side of the Studio Display does nothing when I touch it. So, the power button is hyper sensitive, and the monitor button doesn't function.

    I have to let the computer cool down. Will try reseating the graphics card inside the computer tomorrow.

    Thank you. Any more ideas?
  18. awmazz macrumors 65816

    Jul 4, 2007
    Can't really think of anything other than to upgrade to 10.4(.11) to get access/control of those display buttons. Probably your cheapest option as well.

    I wasn't aware that 10.3 lacked the 'Options' option as it was released concurrently with these displays, so it should. Is the Display preferences panel actually showing it as an 'Apple Cinema Display' (proper name at the top of the panel) with a brightness control slider etc?

    The only other thing I can think of is if you are using an ADC/DVI converter/power-supply instead of plugging it straight into the graphics card. But really that shouldn't be an issue and you should still get the proper ACD display preferences options anyway.
  19. zmttoxics macrumors 65816


    May 20, 2008
    What about electrical tape? No idea if it will work, just suggesting things.
  20. MacLovergr8 macrumors newbie

    May 9, 2009
    This Is What I Found Out

    Hello to everyone that wrote in with suggestions. The best thing I found was this: http://oldsite.auburnschl.edu/Technology/protected/applemanuals/studio_display_15_adc.pdf Service Source manual for the Apple Studio Display 15" LCD (ADC). On page 38 and 39 they talk about the touch switch kit and that the display can experience problems working in close proximity to some wireless devices.

    I did the procedure to access the Options preference for the display and it appears my monitor does not have the touch switch kit installed. (And I'm not going to pay to have it installed.) There is some sort of electric field in my house that is reeking havoc with the switches.

    I moved the computer and monitor far away from the TV, stereo, etc. into the kitchen and the switches worked correctly. Moved the computer back to starting place and same issue. (Just like magic wave my hand and the computer starts.)

    I will have to control the monitor with the power switch on the surge protector.

    Does this make sense to all of you?

    Finding that service manual was a lifesaver!!!
  21. juhlster1021 thread starter macrumors newbie

    Jun 11, 2007
    This sounds insane but I fixed the problem from my orig post

    I eventually narrowed my trouble down to the switch in the bezel too. Started looking on eBay etc for a replacement monitor. My wife, who now uses the Mac, ramped up her suggestions that we just replace the whole computer rather than buy any used parts for this one.

    So, having given up on the otherwise pretty display... and thinking that maybe there was some intermittent short from some wiring / solder proximity issue.... I of course decided to.... PUNCH the lower right corner of my monitor, exactly over the power switch. Not a friendly tap either. I gave it all I had. Twice in a row.

    Immediately the display began working perfectly.

    6 weeks later and it's still perfect.

    Downside: wife no longer encouraging of my buying a new Mac.
  22. Dr.Pants macrumors 65816


    Jan 8, 2009
    :eek: Talk about a self-tech-support success story. Nothing like a little violence to show your electronics who is boss :D
  23. TIFFADEE macrumors member

    Jan 7, 2008

    While I was reading this thread, for good reason, the light on my monitor got bright and then the compurer went off...and maybe you just helped me fix my problem...my old MAC G4 quicksilver 867mhz just started doing this the other day. i checked the energy saver settings & they are fine, i went into the console (advice from a different thread) and found this the last time it happened...while i was reading this post...

    2009-07-05 22:03:30.523 HPEventHandler[149]: DebugAssert: Third Party Client: isReady Can't establish connection with the device[/Volumes/Development/HP/Mac-Sirani/mac-software/components/Common/CommonUtils/Sources/CIAUtilities.cpp:82]
    Debugger() was called!

    right before the computer completely shut down, the startup light on the monitor got brighter and then the screen went black and it shut down. i hooked up a wireless router yesterday and i suppose that could be the problem I'm thinking since i finished reading on and saw other things about wireless stuff being added to the computer...I moved the wireless router to a different place and maybe it wont happen again...

    I have a question...How does this sound...

    I am going to be buying a macmini 4.69ghz to use as a new computer and then use the g4 as an extra hard drive...I had replaced the 120G hard drive in it this past year.

    Does that make sense?

    I am aware that the mac mini has built in airport.

    Does that mean that i dont need this wireless router?

    Is airport a built in wireless-ness???

    Thanks for any help.

  24. zmttoxics macrumors 65816


    May 20, 2008
    Where will you be purchasing a 4GHZ Mac Mini? :p
  25. TIFFADEE macrumors member

    Jan 7, 2008
    MY BAD....I MEANT 2.69 GHZ. I'm gonna get a refurb from apple with applecare.
    sorry for my error....do you think it will work and what about the airport...will that take the lace of a wireless router?

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