G4 Cube Power Button Issues

Discussion in 'PowerPC Macs' started by KyriakosCY, Dec 31, 2014.

  1. KyriakosCY macrumors newbie

    Joined:
    Dec 31, 2014
    #1
    Guys, I have 3 G4 Cubes all in working condition yet one has a strange issue...

    This cube was purchased as non working and then had a cpu, motherboard, vrm & gpu transplanted into it to make it work.

    Other than a broken usb port (pins have been pulled out to un-short it) which will eventually be replaced with one from another motherboard, all is perfect but it does not play nice when a power button is connected.

    If a power button/switch is connected to the motherboard the computer auto-starts as soon as the power cable is plugged in, and the led on both the cube switch and Apple Display power switch flashes rapidly and then switches off and the does this power cycle loop forever..

    Once I completely disconect the power button from the motherboard the computer starts up fine from the screen and works flawlessly and does not auto start up, it powers on once the screen switch is pressed like it should.. I have 3 spare proximity switches other than the ones on my working cubes so I have troubleshooted with 6 switches and cables all with exactly the same results.. If I push the switch connector only halfway into the motherboard port it sometimes works which leads me to believe there is a short on the black power switch connector port on the motherboard, or the broken usb is messing something up, yet it will work perfectly for hours once the switch is disconected..

    Any advice will be great in this situation.

    P.S. On a side note I may have accidentally plugged my Harman Kardon Pro Speakers into the broken usb port and they no longer work. They are not detected on any of my 3 cubes.. I have taken them apart like in the pics attached but I have no idea what to test them for...

    Thanks :)
     

    Attached Files:

  2. KyriakosCY thread starter macrumors newbie

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    Dec 31, 2014
    #2
    One more pic
     

    Attached Files:

  3. poiihy macrumors 68020

    poiihy

    Joined:
    Aug 22, 2014
    #3
    I'd like to see a pic of the broken USB port and the power button :)
     
  4. KyriakosCY thread starter macrumors newbie

    Joined:
    Dec 31, 2014
    #4
    Hi, thanks for the reply :) here are the pics.. As I mentioned I have tried 6 power switches, even the ones from my mint perfectly working cubes have the same issues on this particular cube...
     

    Attached Files:

  5. KyriakosCY thread starter macrumors newbie

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    Dec 31, 2014
    #5
    Sorry for the multiple posts but my iPhone doesnt seem to like uploading more than one pic per reply..
     

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  6. poiihy macrumors 68020

    poiihy

    Joined:
    Aug 22, 2014
    #6
    I have no answer for you but I strongly suggest you desolder and remove that bad USB port asap. You may've destroyed your speaker thing with it so you really should remove it before anything else gets 'accidentally' plugged in. And who knows, maybe your button will function normally after you remove it.
     
  7. ctmpkmlec4 macrumors 6502

    Joined:
    Jul 4, 2014
    Location:
    Lyons, KS
    #7
    I don't think the USB is causing the power-on issues. Try placing scotch tape over the touch-sensitive area of the power button. I cut a piece of an anti-static bag as big around as the U.S. nickel, and placed it on the power switch between the core and acrylic case. This makes the button less sensitive, and in my case stopped the seemingly automatic power-on.
     
  8. KyriakosCY thread starter macrumors newbie

    Joined:
    Dec 31, 2014
    #8
    Thanks for the reply, I still believe there is a short on the Logic Board as I previously mentioned that it happens with 6 different Power Switches 2 of which were removed for troubleshooting from working cubes that do not have the problem. I am warfare of the sensitivity issues with the cube proximity switches, but the problem is not that it starts up automatically, it actually won't startup at all with the power button connected, it rapidly flashes the led on both the cube and the Apple Studio Display and goes into a reboot loop with the same flashes.
     
  9. KyriakosCY thread starter macrumors newbie

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    Dec 31, 2014
    #10
    Thanks for the link. Unfortunateley this does not apply to my situation as I have troubleshooted with and without using the clear case, and also inside the case of another working cube etc..

    I have since found another logic board that also has a broken usb port and it does exactly the same thing. My electronics guy is sticking by his opinion that the usb port has nothing to do with this... Anything else I can try..?

    The parts I have swapped out are: Power Switch, Logic Board, VRM, GPU Riser, GPU, removed ethernet and modem cards incase they were problematic, swapped out cpu, started it up without ide and optical flex cables attached etc etc..

    I cannot think of anything else to try..
     
  10. Mnowell69, Jan 2, 2015
    Last edited: Jan 2, 2015

    Mnowell69 macrumors regular

    Mnowell69

    Joined:
    Jul 4, 2013
    Location:
    Bedford, UK
    #11
    if you disconnect the powerswitch and it works then i am at a loss. never had any problems with mine, so far......
    although i have never powered it up without the case. Now i am curious as to why there is a gasket in the first place.

    The other thing i thought of was the usb port causing electrical interference which cause problems with the switch. Apparently some people had problems with interference from fluorescent lights so who can say
     
  11. KyriakosCY thread starter macrumors newbie

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    Dec 31, 2014
    #12
    I have taken a quick video to illustrate the problem. Here is the link..

    https://www.dropbox.com/s/dzww0616k0ikyyv/G4%20Cube%20Power%20Problems.m4v?dl=0

    The scenario is as follows:

    1. G4 Cube with outer shell removed automatically starts up once the power cable is attached, no buttons are pressed.

    2. Proximity Switch LED and Display Led rapidly flashes and then the whole computer shuts down then auto. startup again and goes into a continuous loop of flashes and restarts.

    3. The power button is pulled from its connector on the Logic Board to completely disconnect it.

    4. Now there is no power button, the Cube is started up from the Display power button and the computer starts up normally and boots into the OS.

    4. Power button is re-attached whilst computer is on and it immediately goes to sleep, then instantly wakes itself up and shuts down.

    5. Computer restarts itself now that the button is attached and goes into the same loop as in part 2...

    Im sure this now clearly shows what I am talking about... :)
     
  12. Mnowell69, Jan 3, 2015
    Last edited: Jan 3, 2015

    Mnowell69 macrumors regular

    Mnowell69

    Joined:
    Jul 4, 2013
    Location:
    Bedford, UK
    #13
    have you tried replacing the whole top plate assembly in one go? Does your power button have a proximity switch plate underneath? the top plate should also have an EMI gasket.
     
  13. jbarley macrumors 68040

    jbarley

    Joined:
    Jul 1, 2006
    Location:
    Vancouver Island
    #14
    As a Cube 'owner-user' I can feel your frustration.
    Have you tried posting your problem on "CubeOwners.com", also they have a ton of info in the different forums, in your case being the 'Cube Hardware support'
    The website does not see a lot of action these days, but it usually comes to life when someone posts a problem.
    Good luck...
     
  14. KyriakosCY thread starter macrumors newbie

    Joined:
    Dec 31, 2014
    #15
    Thanks for all the help guys..! Here is a strange update on the situation..

    After trying to find a solution for over 2-3 months I decided to completely strip down the cube to its very last screw and then rebuild it.. I then applied some tape to the power button as a precaution and connected it and then fitted the acrylic case ontop. It then immediately did it's weird flashy led thing and then the Harman Kardons chimed and the cube powered on for the first time with the power button attached.. It sometimes does not like being moved from vertical to horizontal. If off it may switch on and visa versa if on it may switch off but other than that.......

    I have had it running non-stop playing radio stations for 2 full days and it has not powered off or done anything weird so I guess it seems ok-ish..?

    What do you guys think..? :)
     
  15. gooser macrumors 6502a

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    Jul 4, 2013

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