Specifications

Power Mac G5 (Late 2005) Troubleshooting — General Information 139
Press the reset button on the logic board.
Note: For the location of the reset button, see “Logic Board Diagram” in the Views chapter.
Replace the front inlet assembly and close the computer.
Turn on the computer.
Power-On Self Test: RAM and Processor Verication
A power-on self test in the computer’s ROM automatically runs whenever the computer is started
up after being fully shut down (the test does not run if the computer is only restarted). If the test
detects a problem, the status LED located above the power button on the front of the computer
will ash in the following ways*:
1 Flash: No RAM is installed or detected.
2 Flashes: Incompatible RAM types are installed or RAM installed in wrong slots.
3 Flashes: No RAM banks passed memory testing.
4 Flashes: No good boot images are detected in the boot ROM (and/or there is a bad
sys cong block).
5 Flashes: The processor is not usable.
* Note: The status LED lights up when the power button is depressed at startup. Do not count
this light as one of the diagnostic ashes.
Diagnostic LEDs
Power Mac G5 (Late 2005) logic boards include a set of LEDs to help service providers
troubleshoot the computers. The LEDs are located to the left of the top bank of DIMM slots.
Top bank of DIMM slots
(Bank 1)
Edge of main logic board
LED #1
LED #2
LED #3
LED #4
LED #5
LED #6
LED #7
Use the table on the following page to interpret the LEDs.
3.
4.
5.
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