PJH_HAH

Q: My G4 Powerbook 15 inch laptop (A1046) will only start up if Cmd key is pressed, else it depowers within seconds. How can I clear the faulty virtual memory file from the hard drive?

I may have been careless and rermoved a USB stick and a VGA display while/just after the laptop was powering down into sleep mode.

The power up reaches the chime, then after a few disc access noises seems to power down - unless the Cmd key is held from power on.

 

Can't use 'boot plus hold C' to boot from the Installation disk and wipe the hard drive for a re-install. I believe from reading around that there may be a file stored at power down to help recover from sleep - possibly in the Virtual Memory area which is what the Cmd key inhibits on start up?

A little reading can be a dangerous thing.

 

But if so, how can I clear this damaged file so that I can boot up normally?

 

Peter

PowerBook, Mac OS X (10.3.x), Aluminium

Posted on Dec 11, 2012 9:43 AM

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Q: My G4 Powerbook 15 inch laptop (A1046) will only start up if Cmd key is pressed, else it depowers within seconds. How can I clear ... more

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  • by Texas Mac Man,

    Texas Mac Man Texas Mac Man Dec 11, 2012 3:27 PM in response to PJH_HAH
    Level 8 (46,611 points)
    Dec 11, 2012 3:27 PM in response to PJH_HAH

    Are you depressing the CMD key plus another key? Like CMD + S which boots a Mac in Single-User Mode, a special mode used for troubleshooting and repairing complex hard drive issues.

     

    Will it boot in Safe Mode? See

    What is Safe Boot, Safe Mode? (Mac OS X)

    http://docs.info.apple.com/article.html?artnum=107392

    Takes a while to run, but it usually "fixes" problems.

     

    Troubleshooting portables that won't turn on or start up

    http://support.apple.com/kb/TA25686?viewlocale=en_US

     

    Troubleshooting: My computer won't turn on

    http://support.apple.com/kb/TS1367

     

     Cheers, Tom

  • by PJH_HAH,

    PJH_HAH PJH_HAH Dec 13, 2012 4:53 AM in response to Texas Mac Man
    Level 1 (0 points)
    Dec 13, 2012 4:53 AM in response to Texas Mac Man

    Thanks for your help, Tom. I have been carefully going over the steps I have tried so far.

     

    During boot, holding down shift to run in safe mode - Mac powers off after chime.

      "             , hold down C with Install/restore disc in, - Mac powers down after chime.

      "             , hold Cmd and S - Mac runs up to terminal-style screen of text ending with a localhost:/ prompt.

         not familiar with Unix terminal cmds - but I am boning up. (see later).

    During boot, hold down Cmd, Mac runs up in c 20 seconds to screen visible showing rest of software loading to give nornmal desktop. The published function of Cmd during boot is to disable Virtual Memory.

     

    BTW I have noticed a strange occurrence in that when I click on "detect displays" the "Cancel, Sleep, Restart, Shut-down" dialogue box appears???? Just in case that is somehow being invoked during boot up, I have tried booting up with regular pulses of the Esc key (=cancel) until the screen become visible - and it works!

     

    After mulling over with a colleague & a beer, I am going to start using Unix commands in Terminal to look for the Virtual Memory paged files on the disk, which I believe may hold data stored during turning off that is designed to restore the working conditions after recovery from sleep/shutdown.

    If some of this data is corrupted, and it is read during boot-up after the chime, it could be invoking the Cancel, Sleep, Restart, Shutdown dialogue (still invisible becaiuse the screen is not up yet) with a short time delay before the default (Shutdown) is executed.

    Hence pulsing Esc key during boot which would cancel this dialogue box before Shutdown executes??

     

    Now I need to study Unix commands to ensure I only do passive actions like list files and change directory before I think of moving or deleting files perhaps in due course.

    Perhaps it would be better to use Cmd + S to access the Unix commands, so that no other software is running when I explore with the files on disk? Is this what it's for?

     

    Regards

    Peter

  • by PJH_HAH,

    PJH_HAH PJH_HAH Dec 13, 2012 5:05 AM in response to PJH_HAH
    Level 1 (0 points)
    Dec 13, 2012 5:05 AM in response to PJH_HAH

    I had also carried out the PRAM and PMU reset instruction sequences.

    I have used terminal to invoke the       sudo nvram boot-args="-x -v"     to allegedly enter Safe mode; and Verbose to show the run up scripts. Wish I could parse them myself as they shoot by!

     

    Peter