Apple Xserve G5 - Manual (Page 78)

4 - Xserve G5 Troubleshooting General Information
Power Supply Verification
If the server 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. When connecting the volt meter
leads to specific pins, make sure the power supply remains securely plugged into its
connector on the logic board.
The following figure shows the pins and voltage on the server’s power supply connector,
as viewed from above when it is connected to the logic board.
1. Plug a known-good power cord into the server. Do not turn on the server.
2. Connect the black lead of the volt meter to pin 8 of the power supply connector;
connect the red lead of the volt meter to pin 1. The volt meter should measure
approximately +12V.
If you do not get a reading of +12V, recheck the volt meter connections and measure
the voltage again. If voltage is still not present, replace the power supply.
If you do measure +12V on pin 1, the power supply is likely OK.
RAM and Processor Verification: Power-On Self Test
A power-on self test in the server’s ROM automatically runs whenever the server is started
up after being fully shut down (the test does not run if the server is only restarted). If the
test detects a problem, you will not see a normal sequence of system activity lights on the
front panel during startup. Instead, the Power light will flash in the following ways:
• 1 Flash: No RAM is installed or detected.
• 2 Flashes: Incompatible RAM types are installed.
• 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 config block).
Pin 1 +12VDC
Pin 2 +12VDC
Pin 3 +12VDC
Pin 4 IICclk
Pin 5 +12VDC
Pin 6 +12VDC
Pin 7 +12VDC
GND Pin 8
GND Pin 9
IICdat Pin 10
IICrtn Pin 11
GND Pin 12
GND Pin 13
GND Pin 14