Repair manual

5
Firmware versions
The latest versions are:
1.2 for the early tray loading iMacs (233 – 333 MHz)
4.1.9 for the slot loading iMacs
4.1.9 can only be installed if you have booted OS 9.1 – OS 9.2.2 from a
local hard disk.
Initial comments
DO proceed carefully as it’s easy to make things worse
DO watch and listen carefully for tell-tale symptoms during
(attempts to) bootup
DO find out what version firmware you have, if you can, using the
Apple System Profiler
DO make a note of your OS and iMac model version (you can use
the Profiler again)
DON’T reboot unnecessarily as the problems usually get worse and you
may go from symptom S1 to S2 to S4
AVOID resetting the PRAM at all costs unless you are sure you
have the latest firmware version.
Things worth trying
The suggestions here will help you to update your firmware. This will fix
many iMacs with the symptoms described here, particularly if OS X 10.2
or higher has been anywhere near the iMac.
The installer for the new firmware can be found on the Apple website (see
links above and below) or on the CD for early versions of OS X. You need
to get it onto the hard disk and then run the installer so the firmware is
transferred to the logic board.
If your firmware is already up to date then some of the suggestions may
still help.
If you need to remove a CD that is stuck in the drive try looking here for
tray loaders and here for slot loaders, or refer to your manuals. If the
iMac isn’t starting up properly then you will need to press the emergency
eject button immediately after power-on in order to have it spat out.
1. If you can get the iMac to boot up
1.1 If you have some sort of a visible image on the display then update
your firmware without delay.