Ask Max: My G5 passes the hardware test but won't connect to USB devices...
I have a dual 2G G5 which passes the hardware test for the logic board (both long and short versions) and yet had no response from any of the built in USB ports. The internal modem still shows in the system profiler but no devices attached to any of the built in ports show.
Any thoughts? Is there a USB host controller that is not part of the logic board?
It is possible for the USB system to not allow devices to connect but still fail to register a problem on the AHT logic-board test. Here are two things to try.
-- First turn off your Power Mac G5 and then hold the Power button down until you hear a long tone. Then let go and wait for the computer to reboot and test the USB.
-- If that fails to fix the USB operation, then you should insert the OS X install DVD and set it as the startup device. Power down the computer and remove all extra PCI cards from the machine. With only a USB mouse connected, start it up and see if the USB ports now allow the mouse to function. Try all the ports, including the front port. If the mouse works from the Install DVD, then it could be a software issue and an Archive and Install of the Mac OS should work to repair the damaged system files.