HT3964: Intel-based Macs: Resetting the System Management Controller (SMC)

Learn about Intel-based Macs: Resetting the System Management Controller (SMC)
andrea825522

Q: Help my iMac G4 updated ram and now, when booting I get a black screen

Hi, everyone , I wanted to add more ram and a bigger hard drive, My iMac G4 is a 800mhz with 512mbs of ram and an 80gb hard drive  my serial number is QT*****N0S, and when I put it all back together it goes on with sound and everything but the monitor stays black, I can here it start and it makes the start up noise and everything but the screen stays black did I not connect it right or did some how I broke it, I have put it back together and take it apart aging to make shore I did not miss any thing but it still has a black screen, please help I love this mac.

 

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iMac, Mac OS X (10.5.6)

Posted on Sep 22, 2013 9:41 PM

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Q: Help my iMac G4 updated ram and now, when booting I get a black screen

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  • by rccharles,

    rccharles rccharles Sep 23, 2013 8:59 AM in response to andrea825522
    Level 6 (8,471 points)
    Classic Mac OS
    Sep 23, 2013 8:59 AM in response to andrea825522

    * cmd-opt-p-r -- Zap PRAM. Hold down until second chime.

        * cmd-opt-n-v -- Clear NV RAM. Similar to reset-all in Open Firmware.

     

    let's see if you can get something on the display that doesn't involve the OS.

        * cmd-opt-o-f -- Boot into open firmware

     

     

     

    Then, before the screen lights up, hold down Command-Option-O-F until the Open Firmware screen appears. Then enter these lines, pressing Return after each one:

     

    reset-nvram

    set-defaults

    reset-all

     

    "The reset-all command should restart your Mac. If so, you have successfully reset the Open Firmware settings."

    http://support.apple.com/kb/TS1812?viewlocale=en_US

     

    Should the fail...

    Try taking the battery out for 10 minutes.  Put battery back in.  Cross fingers. Power the machine back on.