TS1935: Power Mac G5: What to do if you see black, white, or no video at start up

Learn about Power Mac G5: What to do if you see black, white, or no video at start up
HDLH
Level 1 (0 points)

Q: G5 PPC everything OK, no display!

Hi,

 

I recently got a mint 1.8 GHz G5 (A1047). Everything seems to run fine (with 10.5.8 I put in a few years ago) except there's no display: the monitor remains black.

And I also can't open the DVD player (nothing happens when the key's pressed). The Apple keyboard comes from another computer and is OK.

 

So I checked the monitor, cable, video card, HDD & RAM on another G5 (2x2 Ghz) and there was no problem : it runs as always.

Only 2 RAM modules were faulty, so I put them away. I kept 2 x 512MB PC3200U modules and tested them successfully in the 2 x 2 GHz G5. They're also correctly installed and in the right slots, as instructed.

 

I also tried the 2 x 2 GHz G5 RAM modules and video card in the 1.8 GHz G5: nothing changed.

Some posts here mentionned resetting the PRAM and the SMU. I did and the 1.8 GHz still got no video.

 

Any idea or clue would be most welcome!

 

Thanks.

 

HDLH

PowerMac, Mac OS X (10.5.8)

Posted on Nov 19, 2013 11:07 AM

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HDLH

Q: G5 PPC everything OK, no display!

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  • Helpful answers

  • by rccharles,Helpful

    rccharles rccharles Nov 19, 2013 12:58 PM in response to HDLH
    Level 6 (8,476 points)
    Classic Mac OS
    Nov 19, 2013 12:58 PM in response to HDLH

    Just to comfirm.  You tried a new video card in the machine & the monitor still didn't work?

     

    I'd be pesimistic about this machine.

     

     

    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.

     

    How to eject a cd from the internal cd drive:

    eject cd

     

    List of devices:

    devalias

     

    List of variables:

    printenv

     

    More than you ever wanted to know about open firmware

    http://www.firmworks.com/QuickRef.html

     

     

    ( nvram is the equivalent Mac OS X terminal command. )

    ---------------------

    Resetting your Mac's PRAM and NVRAM

    http://support.apple.com/kb/HT1379

     

    ---------------------

    reset the PMU

    http://mrjcd.com/junk/PMU.jpg

    http://support.apple.com/kb/ht1939

  • by HDLH,

    HDLH HDLH Nov 20, 2013 4:55 AM in response to rccharles
    Level 1 (0 points)
    Nov 20, 2013 4:55 AM in response to rccharles

    Hi rccharles,

     

    thanks for your answer. I tried your procedure but nothing happened: apparently the monitor receives no input signal and the keboard doesn't respond. Even after removing the battery for more than an hour. I also tried another good battery, unsuccessfully.

     

    For your information the video card I put in the 1.8 G5 is OK and comes from the 2x2 G5. Both are identical. Furhermore, the 1.8 G5 video card runs fine in the 2x2 G5!

     

    I misspelled the PMU (SMU!) I already resetted… So I really don't know what to do next, except dump the machine or sell it for parts.

     

    Thanks anyway for your help!

     

    Best Regards

     

    HDLH

  • by rccharles,Helpful

    rccharles rccharles Nov 20, 2013 9:02 AM in response to HDLH
    Level 6 (8,476 points)
    Classic Mac OS
    Nov 20, 2013 9:02 AM in response to HDLH

    Worth a try, but don't get your hopes up.  I read a post that a bad keyboard cause boot grief.

     

    1) Disconnect all cables.  You do not need keyboard or mouse for normal boot.

     

    2) disconnect hd & cd drives.  Maybe a bad drive is causing the problem.

     

    3) You have checked the memory.  Did you try different slots?  bad memory should give some grief.

     

    Try 2 & 3 option boot.  To see startup manager.

     

    Startup Manager

    Try holding down the option key then power on. This brings up the startup manager. Click on your hd. Click on right arrow key.

     

    Your statup manager may be slightly different, but this is the idea.

    http://docs.info.apple.com/article.html?artnum=106178

     

     

    4) check voltages out of your power supply.  Is there a light on the power supply?

     

    5) Unplug & replug all cables

     

     

     

     

    Robert

  • by HDLH,

    HDLH HDLH Nov 20, 2013 10:25 AM in response to rccharles
    Level 1 (0 points)
    Nov 20, 2013 10:25 AM in response to rccharles

    Hi again Robert,

     

    there's no power supply issue since my 2x2 GHz G5 is currently connected to the same outlet and runs fine.

     

    The keyboard, monitor & video cable comes from this 2x2 GHz G5 and works perfectly.

     

    As the keyboard doesn't respond (when plugged to the 1.8 GHz G5), I can depress the option key as long as I want but nothing happens (on the monitor). So I can't reach Startup manager… (I already tried this earlier anyway)

    Red light goes on and the HDD hums slightly. After a couple of minutes the fans go full blast (though I left the clear side panel on). To me this is a clear sign that the machine can't find its O.S.

     

    Nothing is plugged to this machine (except the monitor & keyboard).

    But I unplugged & replugged its cables anyway and tried to boot after displacing both RAM modules (to the next slots), though Apple instructs to put them on the 1st slot of each bank (starting from the center).

     

    Well… That's about it my friend.

     

    Hervé

  • by rccharles,

    rccharles rccharles Nov 20, 2013 2:45 PM in response to HDLH
    Level 6 (8,476 points)
    Classic Mac OS
    Nov 20, 2013 2:45 PM in response to HDLH

    Oh, a computer power supply is a metal box that converts line voltage to 3, 5, & 12 volts used by computers.

     

    Another thing to check.   At least you will have identified the problem.

     

    G5 has these hardware issues:

      -- bad capacitors on logic board

      -- bad capacitors in power supply

      -- badly soldered video chip

      -- "There were several Mac models with flat panel displays that had bad displays.

          Most had serial numbers beginning with "W8"---the code for one specific factory.

          This affected PowerBooks as well. If that's the case, the rest of the computer

          is probably fine." by Allan Jones in

         https://discussions.apple.com/message/21630224#21630224

     

     

    Google: g5 capacitor replacement kit

     

    More info on capacitor replacement kits

    http://jimwarholic.com/2008/07/how-to-repair-apple-imac-g5.php

    http://thecapking.com/applg5.html

     

    A success story:

    https://discussions.apple.com/message/22751906#22751906

  • by HDLH,

    HDLH HDLH Nov 25, 2013 12:04 AM in response to rccharles
    Level 1 (0 points)
    Nov 25, 2013 12:04 AM in response to rccharles

    Hi Robert,

     

    my mistake: I thought you meant the external AC power supply…

     

    Thanks again for the links & tips but my computer is a PPC G5 not an i-mac.

     

    Best regards,

     

    Hervé