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

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

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.

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

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.

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

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

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.

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