iMac powers on, goes to Apple logo, fan speeds up and freezes

Question

Level 1

0 points

iMac powers on, goes to Apple logo, fan speeds up and freezes

Hi,

I am a HUGE fan of Apple. I have had amazing experiences with the company since December, 2004 when my mom unwrapped an iMac G5.

It is that iMac that I am talking of today. As a bit of a geek, I have had it in my room for about 1 year (after upgrading the hard drive, RAM and adding AirPort). This is a truly amazing machine, especially when used on a TV stand with a BlueTooth keyboard and mouse.

BUT... This morning, I noticed it had frozen. So, I decided to shut it down and reboot it. So out came the power cable and all other cables, and then I put just the power cable in and pressed start. I was greeted by the chime (which I LOVE) and then it went to the loading screen. And waited. And waited. And then, five minutes later, the fans went in to overdrive, the sreen froze, and I could have probably replaced my heater with the iMac it was blowing out so much hot air!

I've reset the SMU, the PRAM and the VRAM, and even tried restarting it in single user mode. Does anyone here know how to fix my iMac?

Any help would be greatly appreciated!

JJJK

iMac, Mac OS X (10.5.8), 17" iMac G5 boot issues

Posted on May 30, 2012 11:56 AM

Reply

Answer 1

May 30, 2012 1:26 PM in response to Triple-J K

Do you see the spinning gear at all? If so, try booting in Verbose mode, then you should see text and the last line usually tells you where the boot did hang.

Have you tried to boot from any installation discs? Put a disc in the drive and hold C. If you still have the original disks you could try Apple Hardware Test, boot from that disc.

Also check capacitors, if you have 2004 model it usually fails with capacitors going bad. Open up the case (http://www.macwiki.nl/wiki/Hoe_kan_ik:IMac_G5_schoonmaken) and take a look at capacitors. If you see something like this: http://www.instructables.com/image/F6WK6L2G3TDN8SZ/The-Imac.jpg

Then the caps are bad. Top of the caps should be perfectly flat, even if they bulge just a little they can be faulty, they may also show no external signs... but usually you can see if they have failed. Caps can be replaced and theya are pretty cheap (quality of course varies a lot). Rubycon has been praised as reliable brand for example.

Reply