Specifications

Power Mac G5 (Late 2004) Troubleshooting - 6
General Information
Front Panel Board Troubleshooting
Certain no power symptoms can sometimes be caused by a failed front panel board or
power button. However, troubleshooting these parts by swapping them out with known-
good parts can be time-consuming. An alternative approach is to build a simple front panel
board troubleshooting tool, as illustrated, and then use the procedures described below to
test the board and button before actually replacing them.
The tool consists of a known-good front panel board, with a known-good power button and
front panel board cable attached.
To use the tool in troubleshooting the front panel board and power button, do the following:
1. Shut down the computer.
2. Disconnect the installed front panel board cable from the logic board.
3. Connect the front panel board cable from the troubleshooting tool to the logic board.
4. Try to start up the computer by pressing the power button on the troubleshooting tool.
Then proceed with the front panel board troubleshooting steps as described in the
“Symptom Charts” in this chapter.
Power Supply Verification
To power on, the computer's logic board requires a “trickle” power of +5V. If the system
fails to power on, first reset the PMU. Then follow the procedure outlined below to
determine whether the problem is related to the power supply.
Note: To verify the power supply, you need a volt meter.
1. Remove the power cord from the computer.
2. Open the computer, lay it on its side with the access side facing up.
3. Remove the front inlet fan assembly.