On Apr 18, 2011, at 12:08 PM, John Hobbs wrote: > > On 18 Apr 2011, at 09:36, william wrote: > > My core duo imac which was having problems with video artifacts and shutdowns > has presented a new problem. Now i am unable to boot up. It goes to the > screen with the Apple logo then the wheel just spins over and over. I am able > to boot up on my Snow Leopard cd, from which i have repaired disk and > repaired permissions. It says both are ok, but i still cannot boot past the > Apple logo window. Is this the end, or are there more things i can do to try > to extend its life for a few months till i can get another intel imac? For > now i am back on my G4 imac running Tiger. Feeling alot less powerful, but > much more secure. > > Thanks for any suggestions. > > -william
> My suggestion would be buy an external firewire hard drive, install Snow > Leopard and use this as startup disc. It won't be money wasted as you can > continue to use it when you get your new Mac. > Question. When you boot from CD (DVD) does the internal drive show up and can > you access the files on it? > Good Luck > John An external hard drive as a boot device may work, but I suspect it won't. Based on your description, your iMac was having video problems, including on-screen artifacts and shutdowns. The problem now has worsened to the point where it will light up the screen while running in a low-video-demand state (grey screen with spinning wheel, from a disc in an optical drive), but will freeze when the iMac is tasked with meeting the full video demands of OS X. All of those symptoms mean you've got faulty video circuitry on your logic board, and you can expect the problem to worsen to the point you won't get a chime and the screen won't light up. And that means a new logic board, unless you want to try having one of many repair facilities on eBay and elsewhere give a whack at fixing the problem. This usually involves reflowing the hundreds of tiny solder balls that affix the video chip to the logic board, thus healing one or more broken/cold solder joints that caused your initial artifacts, then shutdowns and now refusal to boot to the OS X desktop. Some vendors offer to reball or replace all the solder joints; check their references carefully if you decide to go this route. Another way to verify my suspicion is to power on the iMac, then hold down the Shift key until it boots into Safe Mode. My hunch is that, at this point, it probably will get to the desktop. Why? Because the video demands of OS X in Safe Mode are not much more than they are before the boot sequence tries to switch to the OS X blue screen. Yet another way to confirm a bad logic board/video issue is to connect an external monitor. (You may have to boot into Safe Mode to set it to work properly.) If the external monitor displays the same artifacts and symptoms as your internal monitor, then you know it's the logic board/video circuitry. Based on your description, I do not expect your machine will boot and run with an external monitor connected. However, I have seen one or two cases where the built-in LCD was the problem and not the video circuitry/logic board. In those cases, someone had been inside the Mac earlier and caused the problem/failure somehow. And yet another way to confirm my diagnosis is to boot from the Apple-supplied disc that contains the Apple Hardware Test. Run both Quick and Extended tests, and I suspect the tests may freeze at the point near the end where the video tests run, displaying a FAILED notice at the same time. But maybe not, because the test is running in the low-video-demand mode. I've seen many Macs pass the AHTs yet have definite video issues. Good luck. Jim Scott -- You received this message because you are a member of the iMac Group, a group for those using Apple iMacs and eMacs. The list FAQ is at http://lowendmac.com/imac/list.shtml and our netiquette guide is at http://www.lowendmac.com/lists/netiquette.shtml To post to this group, send email to imaclist@googlegroups.com To leave this group, send email to imaclist+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/imaclist
