Specifications

Power Mac G5 (Late 2005) Troubleshooting — Symptom Charts 145
Verify that processors’ mounting screws are properly tightened.
Reseat front panel board.
Test whether the front panel board or power button is at fault. Remove the installed front
panel board and swap it for a known-good front panel board.
Replace front panel board.
Replace power button.
Replace power supply.
Replace logic board.
Power-on LED illuminates when pressed in, but goes out when button is released,
there is no boot tone or video, but you can hear a small click
Remove the power cord.
Open the computer and lay it on its side.
Remove the processor heatsink cover.
Using an ohm meter, measure the resistance across Terminal 1 and Terminal 2 for CPU A.
(Refer to the Power Supply Verication photo for terminal locations.) Hold the meter’s
probes on the terminals for 5 seconds minimum. Nominal resistance readings should be
above 200 ohms. If the resistance is below 10 ohms, replace the power supply.
Check for trickle voltage from the power supply. Refer to “Power Supply Verication” in this
chapter. If verication fails, replace power supply.
Verify that the processor module is properly seated. Check diagnostic LED 1 and/or LED 6.
Verify that the processor mounting screws are properly tightened.
Replace the power supply.
Power-on LED illuminates when power button is pressed but fans do not spin (or
spin only momentarily) and there is no boot tone or video
Reseat video card. (Make sure video card is fully inserted in connector and end of card is
secured by the connector latch.) For video cards that require power cables, check that they
are connected.
Reset logic board. Refer to “Resetting the Logic Board” in this chapter.
Verify power supply cables are fully connected and power bus bar screws are tightened.
Check diagnostic LED 1 and LED 6 for processor connection.
Reseat processor and check for bent pins.
Check for trickle voltage from the power supply. Refer to “Power Supply Verication” in this
chapter. If verication fails, replace power supply.
Replace logic board.
Replace processor.
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