Apple power mac g5 june 2004 User Manual

							
Power Mac G5 Troubleshooting 187

Power-on LED illuminates when power button is pressed, fans spin, and boot tone 
chimes, but there is no video
Reseat video card. (Make sure video card is fully inserted in connector and end of card is 
secured by the connector latch.)
Reset PRAM (restart computer while holding down Command-Option-P-R keys until second 
boot tone chimes)
Replace video card
Reset logic board. Refer to “Resetting the PMU on the Logic Board” in this chapter.
Replace logic board
Power-on LED does not illuminate when power button is pressed, but fans spin, 
boot tone chimes, and there is video
Reseat front panel board cable
Replace front panel board cable
Test the front panel board and power button using the front panel board troubleshooting 
tool. Refer to “Front Panel Board Troubleshooting” in this chapter. If the computer starts up 
correctly, go to step 4. Otherwise, go to step 7.
Test whether the front panel board or power button is at fault. Remove the installed front 
panel board and swap it for the known-good front panel board in the front panel board 
troubleshooting tool. Then connect the troubleshooting tool to the logic board of a 
known-good Power Mac G5 and start it up using the tool. If the computer does not start up 
correctly, go to step 5. Otherwise, go to step 6.
Replace front panel board
Replace power button
Replace logic board
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188 Power Mac G5 Troubleshooting

Startup Failures for Power Mac G5 (June 2004 Dual 2.5 GHz/
Early 2005 Dual 2.7 GHz)
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.)
Reset logic board. Refer to “Resetting the PMU on the Logic Board” in this chapter.
Verify power supply cables are fully connected
Reseat the processor
Replace the processor
Check for trickle voltage on the power supply connector. Refer to “Power Supply 
Verification” in this chapter. If verification fails, replace power supply.
Replace logic board
Power-on LED illuminates when power button is pressed and fans spin 
continuously but 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.)
Verify speaker cable is fully seated.
Reset logic board. Refer to “Resetting the PMU on the Logic Board” in this chapter.
Reseat the processor
Replace the processor
Replace logic board
Power-on LED illuminates, fans spin up, no boot tone, and the system shuts down 
within a few minutes
Reseat the processor
Replace the processor
Replace the logic board
Replace the power supply
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Power Mac G5 Troubleshooting 189

Power-on LED illuminates, fans and processor pump run harder, there is no boot 
and the system shuts down within a few minutes
Remove the processor and look for loss of fluid on the absorbent liner on top of the power 
supply. If you see drops of fluid, replace the processor, otherwise go on to the next step.
Reseat the processor. 
Replace the processor
Replace the logic board
Replace the power supply
Fluid leak is suspected and the computer is plugged in
Unplug the computer
Put on rubber gloves if handling a liquid cooling module that is leaking or suspected to be 
leaking
Remove the processor
Wipe the spill using rags, paper towels, or other suitable material. Contain and dispose of the 
cleaning materials according to locals laws and regulations.
Wash the skin with running water
Replace the processor
Replace modules that show corrosion to the traces or solder joints.
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190 Power Mac G5 Troubleshooting

Fans  
Individual fan failure
Replace fan 
Exception: The drive fan and blower located between the optical and hard drives cannot be 
replaced. You must replace the enclosure for these two parts.
Replace logic board
All fans run at high speed
Run Apple Service Diagnostic (refer to “Thermal Calibration” earlier in this chapter).
Media bay fans run at high speed
Note: If any of the following three conditions cannot be verified, the red LED on the logic board 
near the front panel board will be lit.
Verify that the clear plastic air deflector door is in place.
Verify that the white sensor label is not damaged and is in place on the lower right tab of 
the air deflector door.
Verify that the air deflector sensor board is operating properly. 
Note: You can differentiate a bad sensor label from a bad sensor board by the following: 
Remove the air deflector door. Slide a folded piece of paper through the slot in the enclosure 
where the right tab of the air deflector would normally be inserted. If the red LED goes out 
(but stays on with the door in place), the sensor label on the door is missing or damaged. 
Check the sensor cable connection on the logic board (second from right connector located 
directly below the hard drives).
Replace the logic board.
Replace the air deflector sensor board.
Computer goes to sleep for no apparent reason
Two additional symptoms: The system log typically includes a message similar to: “PowerMac7,3 
Thermal Manager: Thermal Runaway Detected: System Will Sleep.” The customer may also note 
that the fans ramp up to a higher speed shortly before the computer sleeps. 
Update the operating system to Mac OS X 10.3.6 or above. 
If the system log still reports Thermal Runaway, replace the processor module.
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Power Mac G5 Troubleshooting 191

Other Failures
Duct door sensor 
Reseat interlock sensor board cable
Replace interlock sensor board
Replace logic board
Replace enclosure
Hard drive (kernel panics, hard drive does not mount, or performance slows when 
second hard drive is installed)
Replace hard drive guide screws
Replace hard drive
Optical drive 
Replace optical drive cable
Replace optical drive
Replace logic board
FireWire port (front panel A) 
Reseat front panel board cable.
Replace front panel board cable
Replace front panel board
Replace logic board
Firewire port (rear AB) 
Replace logic board
Firewire port (rear BB) 
Replace logic board
Internal speakers (left or right fails, boot tone) 
Replace logic board
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192 Power Mac G5 Troubleshooting
Internal speakers (high-pitch tone) 
Replace power supply
Replace logic board
USB 2.0 (front port) 
Replace front panel board cable
Replace front panel board
Replace logic board
USB 2.0 (rear-top port or rear bottom port)
Replace logic board
Modem
Replace modem
Replace modem filter board
Replace logic board
AirPort 
Replace AirPort Card
Replace antenna card
Replace logic board
Bluetooth 
Replace Bluetooth card
Replace antenna card
Replace logic board
Audio IO (front line in  headphones)
Replace front panel board cable
Replace front panel board
Reposition logic board
Replace logic board
Audio IO (rear line in  line out; rear line out  line out) 
Replace logic board
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 Service Source
© 2005 Apple Computer, Inc. All rights reserved.
Upgrades
Power Mac G5 
						

							
Power Mac G5 Upgrades — Modem Upgrade Kit 195
Modem Upgrade Kit
Apple offers a modem board as a configure-to-order (CTO) option for the Power Mac G5 (Early 
2005) computer. For customers who purchase this computer in retail or want to add a modem 
board after purchase, Apple will provide an upgrade kit for Apple Authorized Service Providers. 
Installation of the upgrade kit must be performed by an Apple Authorized Service Provider. 
Damage resulting from installation by anyone other than a service provider will not be covered 
under the product’s warranty.
The upgrade kit is available on GSX. Authorized Service Providers that are also Apple Authorized 
Resellers may purchase the upgrade kit from the Apple Reseller store.
Tools
The only tools required for this procedure are a Phillips and a small, flatblade screwdriver.
Preliminary Steps
Before you begin, open the computer, lay it on its side with the access side facing up, and 
remove the speaker/fan assembly.
Part Location 
						

							
Power Mac G5 Upgrades — Modem Upgrade Kit 196
Procedure
Note for Chinese Installations Only: The Chinese upgrade kit includes a China-specific label that 
you must apply to the modem. To attach the label, remove the protective backing and wrap the 
label around the modem as illustrated below.
Connect the modem filter cable to the connector on the end of the modem board. 
 
 
 
 
 
 
 
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Power Mac G5 Upgrades — Modem Upgrade Kit 197
Connect the modem to the modem connector on the logic board and install the two 
mounting screws.  
With a small, flat-blade screwdriver, pry up and remove the modem plug on the computer’s 
back panel. 
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