intel imac with 10.4 Tiger crashes on boot

[Mainstwebguy]

Hello guys,

I've been running my imac for about 3 years and have never had a problem until last week. It randomly crashed (screen darkened and told me i had to reboot in a couple different languages) so i rebooted and then it ran ok for another few days. Yesterday it crashed again and when i rebooted it crashed before getting past the gray screen with the spinning wheel.

To troubleshoot i followed all the things on the post i saw here: http://guides.macrumors.com/Mac_doesn't_boot but nothing is working. I am able to run the hardware test successfully and no problems were found. next i tried to get it to boot from the original install disk that came with the computer to run the disk utility but i was unable to get that to run (it crashes at the gray screen).

Then i tried to boot in safe mode which again crashes at gray screen (when holding shift on boot, it take considerable more time on the gray screen before crashing).

I'm starting to get pretty frustrated. I've never really troubleshot problems on a mac because it's been working so well i've never had any real issues with it.

I'm not sure if this is an advantage or not, but i have all my important info stored on an external hard drive so i am definitely not against wiping the drive and starting fresh but i'm not even sure how to do that lol.

What do you guys think? Any info or suggestions are greatly appreciated.

 

[smirk]

Hi,

The fact that you can't even boot from the original install disc leads me to believe there is a hardware issue. However, the fact that your computer passed the hardware test makes this confusing.

This is a long shot, but try unplugging all other devices besides the keyboard and mouse and see if anything changes. I've seen a computer power itself off before due to a faulty keyboard. So maybe even unplug the keyboard and mouse and see what happens. Also perhaps try leaving only the keyboard connected and booting up on the original install disc.

But I'm wondering if you have some faulty RAM, although I've never heard of RAM failing so absolutely that it prevents the computer from booting yet passes a hardware test.

 

[KenwoodIT]

How are you booting to hardware test?

Which hardware test are you running on the machine? Are you running AHT from the discs that came with it?

If you can boot from the AHT disc and run the test, you should be able to boot from the OS disc as well.

Try this:
First, reset the SMC on the unit by unplugging it completely, then clearing all power from the board (once unplugged, hold the power button down for about 15-30 seconds.)

Next, rest the PRAM (restart the computer while holding down command+option+P+R. Wait for at LEAST 3 chimes before letting go.

If your machine is not chiming, it is not passing the power on self test (or POST) If this is the case, look for any blinking coming from the power indicator light on the front of the unit. If it is flashing at all, your issue is most likely either failed RAM or MLB.

If the machine does chime but the symptoms persist, listen for any unusual noises (grinding, screeching, high fans, etc) as those would also be an indicator of a hardware failure.

Another way to try to boot from disc would be rather than holding the "c" key down (or "d", depending on the machine) while booting, try to hold down the option key instead to bring up the boot volume selector. Click on your install disc icon and hit the arrow to move forward and you should be able to boot to the installer and run the disk utility.

If those options fail to work, I suggest taking it to a service provider.

Any machine running 10.4 will most likely be pretty expensive to repair if it is a hardware issue, especially MLB failure.

Hope this helps.