Power Mac G5s are becoming increasingly scarce, and other than the occasional liquid cooling system (LCS) failure, we don’t see many in for repair. The other day, though, I received a June 2004 Power Mac G5 with some interesting freezing issues. This machine and its apple desktop connection (ADC)-based display were both checked in and I basked in their former glory.
I booted up the machine and was greeted with a spinning beach ball just after login began (auto-login was enabled). I forced a shut down by holding the power button and rebooted into safe mode by holding down the shift key on the connected keyboard. The machine went straight to the desktop after a longer-than-usual boot process—part of the safe mode boot process is the “repair disk” function found in Disk Utility, which can add up to five minutes or so to the process. I tested the unit with an Apple-supplied diagnostic suite, but that didn’t yield anything useful (it rarely does).
I then booted the computer from a known-good installation of Mac OS X on an external FireWire drive, and was able to replicate the issue there. Is this hardware or software? The graphics card in the Power Mac was an ATI Radeon 9800 Pro, so I pointed Safari to the new AMD/ATI website and found updates to the Macintosh drivers. I downloaded and copied these updated drivers to a USB drive, rebooted the Power Mac into safe mode, installed the drivers, and restarted. The same problem was present. Even with the “updated” drivers, the Mac still refused to log in fully to the Finder.
In the end, I replaced the ATI card with an NVIDIA card that also had the ADC connector, and our customer is back in business. It seems something was wrong with the ATI card, but the experience taught me that portions of the video drivers do not load until completion of the login process.