Sandie Cohen

Q: iMac G5 (iSight) Black Screen and Won't Start...HELP!

Hi,

 

I have an iMac G5 (iSight) PPC, 2005, model 1145.  All was running well until a couple of weeks ago (see post/thread https://discussions.apple.com/message/16191999#16191999), when I had an issue with a grey screen, no start, and spinning wheel.  Through a series of replies, it was determined that I probably had a corrupt file in the OS (10.5.8).  I did an Archive and Install of the OS and all was running very smoothly....until....NOW!!!!!!!

 

At this point, I cannot start up at all.  When I turn on the computer, I get a 'light', but in a few moments, the fan gets loud, stays loud, and the screen is just black.

 

I tried to start up from my Leopard Disk, hoping I could run the utility....but that didn't work....AND NOW I've the install disk stuck in the drive!!!!!

 

I also thought it might just be some bad RAM, so I took that out and tried to start up again, but that didn't work either.

 

At this point, I'm clueless and hope that someone might be able to offer some good advice.

 

Thanks,

Sandie

Mac OS X (10.5.8)

Posted on Oct 9, 2011 1:25 PM

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Q: iMac G5 (iSight) Black Screen and Won't Start...HELP!

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  • Helpful answers

  • by techiesteve,

    techiesteve techiesteve Oct 9, 2011 1:41 PM in response to Sandie Cohen
    Level 2 (159 points)
    Oct 9, 2011 1:41 PM in response to Sandie Cohen

    Hi Sandie, this doesn't look good. If the problem related to the OS or hard drive, the display would not be black. On a G5 based Mac the fan will run fast if it can't find a bootable system, but this doesn't happen as quickly as you indicate. Does the power light go out shortly after powering on, or does it stay on?

     

    Steve

  • by Sandie Cohen,

    Sandie Cohen Sandie Cohen Oct 9, 2011 1:56 PM in response to techiesteve
    Level 1 (15 points)
    Oct 9, 2011 1:56 PM in response to techiesteve

    Hi Steve,

     

    I had that feeling ;-(....

     

    Anyway, I just tried to boot the iMac and this is what the scenario is:

    Push Power Button....Power Light comes on  and stays on....at the onset, there's a 'gurgle' sound and a sound as if it's trying to maybe read the disk...screen is obviously black the whole time....the sounds stop after about 20 seconds, all the while the Power Light is solid (though its intensity wavers)...and then, around 10-15 seconds later, the fan kicks in and runs fast.  Power Light is still on.

     

    Sandie

  • by Elliot Jordan,

    Elliot Jordan Elliot Jordan Oct 11, 2011 9:50 PM in response to Sandie Cohen
    Level 3 (575 points)
    Oct 11, 2011 9:50 PM in response to Sandie Cohen

    Sounds like a failing hard drive, unfortunately. Back up your files, if you haven't already.

     

    Hard drives are cheap, but it may not be worth it to repair a computer this old.

  • by techiesteve,

    techiesteve techiesteve Oct 11, 2011 11:14 PM in response to Sandie Cohen
    Level 2 (159 points)
    Oct 11, 2011 11:14 PM in response to Sandie Cohen

    Sandie, based upon your description of the problem, it sounds most likely the logic board has failed. Proprietry parts from Apple are no longer available for the G5 series, and even if it was the cost wouldn't have been viable on an older Mac.

     

    If the the problem had been the hard drive, a repair may have been viable depending upon how much you were charged for labour, drives are cheap. In your case the fact that the display is blank indicates it can't be the hard drive causing this fault.

     

    Steve

  • by Sandie Cohen,

    Sandie Cohen Sandie Cohen Oct 12, 2011 6:18 AM in response to techiesteve
    Level 1 (15 points)
    Oct 12, 2011 6:18 AM in response to techiesteve

    I suspect, too, that it is the logic board or perhaps the hard drive, and appreciate your confirmations.

     

    In either case, I think that the iMac is simply 'gone' and not worth the time or money to repair.  I actually began reading how to disassemble the iMac to replace the HD, but as it has an iSight, it is very involved and beyond my inclination and abilities to date.

     

    So....a few more quick questions if I might:

     

    1.  The iMac was connected to an Apple Base Station/Time Machine.  Once it started to give me trouble, I stopped the Time Machine back ups.  I'm assuming all the files/sofware are there.  So, transferring the files should be pretty easy on a new machine....right?  Is that done in migration?  Will Apple do that for me with a new machine?

     

    2.  As the iMac was OS 5.8 and the new machines have the newest OS, would it be advisable to begin anew...i.e. add all the software and settings fresh and then just transfer individual files?  Or, is it okay to just transfer everything from the Base Station/Time Machine? 

     

    3.  The issue of the stuck Leopard disk in the drive on the iMac.  Short of just writing this up to a loss, too, is there a way to get the disk out of the iMac at this point?  Since I cannot boot up, I've been unable to eject it ;-(.  I have another computer running OS 5.8 (also a G5 PPC), so I really need the disk in case of issues with the other computer.

     

    Thanks again for your time and help with this.  It's very much appreciated.

     

    Sandie

  • by MGW,

    MGW MGW Oct 12, 2011 8:06 AM in response to Sandie Cohen
    Level 7 (27,026 points)
    Oct 12, 2011 8:06 AM in response to Sandie Cohen

    3.  There is a way to get the disc out.  Hold the computer on its side and shake it - when you see the tip of the CD in the slot, grab it with a pair of tweezers and pull it out.

     

    1.  TM backups should be fine, format the new machine and then use the Restore function of TM.

     

     

    2.  Use Time Machine.  However, you can use drag and drop, but TM should get everything you want over and you can ditch the stuff you don't need or that is Rosetta.

     

     

     

     

    excellentsig2.png

  • by Sandie Cohen,

    Sandie Cohen Sandie Cohen Oct 12, 2011 8:49 PM in response to MGW
    Level 1 (15 points)
    Oct 12, 2011 8:49 PM in response to MGW

    3.  I shook and I shook...but could not see the tip of the CD.  I'm also a bit frightened about scratching the CD.  ;-(

     

    Any other methods/ideas/thoughts?

     

    Thanks

  • by techiesteve,

    techiesteve techiesteve Oct 12, 2011 10:49 PM in response to Sandie Cohen
    Level 2 (159 points)
    Oct 12, 2011 10:49 PM in response to Sandie Cohen

    Hi Sandie, as the iMac isn't booting and there is no control what so ever over the optical drive, there will be a metal gate down over its slot. This will stop the disk from rolling out when you rotate the iMac. There will only be one option, to  dismantle the iMac. If you were to do this, remove the mememory cover and other torx screws in its base, then use 2 credit card size bits of plastic (not your cc, you'll damage it). Slightly curve one end up to 25 - 30% in. Insert the plastic strips in each end of the top ventation slot with the curved end down, and push to release the 2 hidden spring steel clips. You should be able to find a Youtube movie that shows this.Then swing the front off from the bottom. Peel back the black covering brom the bottom and sides of the LCD panel. Two small torx screws hold the end of the LVDS cable going from the logic board to the rear of the LCD, remove these. 2 torx screws, believe they are T8, are to be removed from each side of the LCD panel. Carefully lift up the LCD panel from the bottom and pull out the backlight connector. The LCD will swing back, held by the black screen. Everything will now be exposed. You will then be able to remove the optical drive, and removing around 5 small pozi screws from its top plate will allow you to remove your Leopard DVD without damaging it. At this point you can also remove the hard drive, if you are dumping the iMac you don't really want any personal information going with it.

     

    Steve

  • by Sandie Cohen,

    Sandie Cohen Sandie Cohen Oct 13, 2011 5:39 AM in response to techiesteve
    Level 1 (15 points)
    Oct 13, 2011 5:39 AM in response to techiesteve

    Thanks....again!  I suspected that shaking the iMac wasn't the answer.  Having probed the slot a bit, I just hope that I haven't damaged the disk.....but if there is a 'metal gate' as you describe, perhaps the disk is still okay.

     

    I will try to disassemble the iMac per your wonderful step-by-step instructions and the movie on YouTube.  As I am going to dump the computer at this point, I suppose I've not much to lose except my time.

     

    That said....If I cannot get this opened and remove the hard drive (yes, I don't want my personal info out there), is there something else I can do to it?  Would, for example, soaking the iMac destroy the HD??

     

    Much appreciated

    (not-so-techie)sandie

  • by ancientscream,Helpful

    ancientscream ancientscream Feb 21, 2012 5:22 PM in response to Sandie Cohen
    Level 1 (20 points)
    Feb 21, 2012 5:22 PM in response to Sandie Cohen

    Just repaired my iMac G5 with complete boot failure, it all came down to capacitors, there was an industry wide use of sub standard/sub spec capacitors at the time the imac G5 was manufactured, due to a manufacturer using a capacitor recipe missing one ingredient, This caused the imac G5's to fail at a much faster rate than they should have done, I had to replace half the capacitors in the power supply and 5 of the higher rated capacitors nearest the power supplies internal vent onto the logic board once this repair was affected, my machine worked perfectly.

     

    take the cover of the back of you imac G5 and see whether your imac version has some led diagnostic lights and check whether the power diagnostic led light lights up properly when started, there are tutorials for this on the web also a light there that indicates whether gpu is communicating with the display properly. all led internal green lights should light up, apart from the right hand one of the four.

     

    with your dark screen and sleep light on symptoms it seems quite likely a surface mount BGA graphics chip failure, but to be honest it could also be a capacitor related issue, if your not into stripping the machine down and soldering capacitors then the machine for you is probably a right off, just try a pram reset boot before giving up, I had similar sleep light no boot scenario on a macbook pro, and a full stripdown got it booting again.

     

    the power supply in the imac G5(als version at least) gets very hot and has no fan of its own and is dependant on the one internal left hand open motherboard fan for its cooling in my opinion it gets too hot, there is also no temp sensor for the power supply to give you an indicator as to how hot its getting, I feel the the heat venting from the overheating power supply internally is what cooked the capacitors nearest it, this is a flaw in the design of this machine. One way to reduce this issue is to perhaps use some kind of extra fan control software to boost the based speed of motherboard fan, whilst at the same time placing and extra entry quality pc fan thin filter foam on intake underneath to prevent any extra dust intake because of the fan speed increase so as to protect the machine from clogging with extra dust and heating the power supply further

  • by MGW,

    MGW MGW Feb 21, 2012 5:33 PM in response to Sandie Cohen
    Level 7 (27,026 points)
    Feb 21, 2012 5:33 PM in response to Sandie Cohen

    There is no "metal gate", there is a felt surround to the optical slot, however.  I have used the tweezer method on my G5 and it worked.

     

     

     

     

    excellentsig2.png

  • by yoshi34,

    yoshi34 yoshi34 Oct 23, 2013 4:00 AM in response to Sandie Cohen
    Level 1 (0 points)
    Oct 23, 2013 4:00 AM in response to Sandie Cohen

    just do a safe boot support.apple.com/kb/HT1455