Apple power mac g5 late 2004 User Manual

							
 
© 2004 Apple Computer, Inc. All rights reserved. 
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Service Source
Troubleshooting 
Power Mac G5 (Late 2004) 
						

							
 
Power Mac G5 (Late 2004) Troubleshooting -   
1  
 General Information 
General Information 
DDR Memory 
In the Power Mac G5, PC3200/400 DDR-SDRAM DIMMs must be installed in pairs of 
equal size and speed. Memory from older Macintosh computers is not compatible. Do not 
try to install non-DDR memory as it will not 
fit in the DIMM slots and could cause damage.
The computers ship with a minimum of 256 MB of RAM, provided by a pair of 128 MB 
DIMMs installed in the two DIMM slots marked “1.” You can add DIMMs, provided they are 
installed as a pair of equal size, in the two DIMM slots marked “2.” A diagram on the logic 
board near the DIMM slots illustrates how the pairs must be installed.  
						

							
 
Power Mac G5 (Late 2004) Troubleshooting -   
2  
 General Information 
Results of Mixing PC2100, PC2700, and PC3200 RAM 
The table below describes what happens if you install PC2100, PC2700, or PC3200 
memory in the Power Mac G5 computer.  
PCI and AGP Cards 
Power Mac G5 computers have four expansion card slots, three of which accommodate 
Peripheral Component Interconnect (PCI) cards and one that accepts an advanced 
graphics port (AGP) video card. AGP cards and PCI cards have different connectors, so 
you cannot insert a PCI card into the AGP slot.
 
Note:
 
 Maximum power consumption for all four expansion slots (the three PCI expansion 
cards and the AGP card) should not exceed 90 watts (W).  When only PC2100 DIMMs are 
installed
The computer makes three single tones 
instead of the startup sound. The LED on the 
front of the computer 
flashes three times, and 
the computer does not startup.
When a mix of PC2100, PC2700, or 
PC 3200 DIMMs is installed The computer starts up normally, but neither 
the computer nor Apple System Pro
filer 
recognizes the PC2100 memory.
When no memory is installed or 
memory is not installed correctly The computer does not make a normal startup 
sound. Instead, there is a single tone, and the 
computer’s front LED 
flashes about once 
every 5 seconds. 
						

							
Power Mac G5 (Late 2004) Troubleshooting - 3
 General Information
AGP Cards
The AGP video card, installed in slot 1, contains the graphics processor unit (GPU) and 
provides the computer’s display ports. Slot 1 is designed speci fically to accept AGP cards. 
Note:  Certain high-performance AGP graphics cards, when installed in slot 1, block 
access to the adjacent PCI slot. In this case, PCI cards can be installed in slots 3 and 4 
but not in slot 2.
PCI Cards
The remaining three expansion slots, labeled 2, 3, and 4, accommodate PCI cards up to 
12 inches long. The PCI slots can accommodate mixed-voltage (5.0 V, 12 V, or 3.3 V) 
cards but only at 3.3 V signaling, with 32-bit or 64-bit data widths and a 33 MHz frequency. 
You can add a 66 MHz card to a 33 MHz PCI slot if the card can operate at the lower 33 
MHz rate.
Warning:  Installing PCI cards that function only at 66 MHz could damage the comp\
uter. 
However, cards that run at both 66 MHz and 33 MHz may be installed. Check with the 
card’s manufacturer to see if a 66 MHz card also works at 33 MHz. 
						

							
Power Mac G5 (Late 2004) Troubleshooting - 4
 General Information
Block Diagram
3535
64
64 3
2
64
32
8
8
8 8
16
3
2
Elastic
Interface
Hyper-
Transport AG
P
PCI
SATA
SATA
EATA 133
PCI
AGP Pro 8x
ADC
64b / 33 MHz PCI
Vesta
5 1/4” Optical 3 1/2” HD
Internal
Speaker
Line out
184 pin Unbuffered DDR DIMM
I2
S
I2 SOptical S/PDIF in 
Optical S/PDIF out
Line in
Bluetooth
Antennas
Rear USB 2.0
Mode
mRJ-11
Front Panel
FireWire 
AFireWire B
Ethernet
RJ-45 USB 2.0
FireWire A
Headphone
Shasta U3 Lite
GPUL PowerPCProcessor
10S process
NEC USB 2.0
Soft ModemI2 S
XGC
CS8416
PCM3052 
						

							
Power Mac G5 Troubleshooting - 5
 General Information
Resetting the Logic Board
Many system problems can be resolved by resetting the logic board. Because the Power 
Mac G5 (Late 2004) uses a System Management Unit (SMU) controller ch\
ip rather than a 
Power Management Unit (PMU) controller chip, the logic board does not include a reset 
button. Instead, to reset the logic board, do the following:
1. Shut down the computer.
2. Unplug the computer from its power source. 
3. Wait 15 seconds.
4. Plug the power cord back in, and turn the computer on. If the computer does not 
power on, there is something else wrong with it; refer to the “Startup Failures” section 
of “Symptom Charts” in this chapter.
Note:  The above procedure resets the computer’s PRAM. After resetting the logic board, 
be sure to reset the time, date, and other system parameter settings.
RAM and Processor Veri fication: Power-On Self Test
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  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).
• 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  flashes. 
						

							
 

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 computers 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. 
						

							
 

Power Mac G5 Troubleshooting - 
 
7
 
 General Information4. Remove the black plastic cap covering the 24-pin power supply cable connector (the 
P1 or largest connector). The cap  fits tightly over the connector. To remove it, rock the 
cap gently forward and backward as you lift up.
 
Note:
 
 This is a top view of the connector when it is plugged into the logic board
5. Press the release latch on the power supply connector and disconnect the cable from  the logic board.
6. Plug a known good power cord into the computer. Do not turn on the computer.
7. On the power supply cable connector: connect the black lead of the volt meter to pin  23 and connect the red lead of the volt meter to pin 1.
 
Note:
 
 This is a bottom view of the connector when it is unplugged and facing up.
The volt meter should measure approximately +5V. If you do not get a reading of +5V, 
recheck the volt meter connections and measure the voltage again. If the voltage is still 
not present, replace the power supply. 
						

							
8 - Power Mac G5 Troubleshooting
 Symptom Charts
Symptom Charts
How to Use the Symptom Charts
The Symptom Charts included in this chapter will help you diagnose specific symptoms 
related to the product. Because cures are listed on the charts in the order of most likely 
solution, try the cures in the order presented. Verify whether or not the product continues 
to exhibit the symptom. If the symptom persists, try the next cure. 
Note:   If a cure instructs you to replace a module, reinstall the original module before you 
proceed to the next cure.
Important:   The only way to shut off power completely to the computer and display is to 
disconnect their power plugs from the power source. Make sure the power cords to the 
computer and display are within easy reach. 
Startup Failures
When testing a computer for the following symptoms, remove the side access panel so 
you can better observe or listen for fan movement.
Note:  For more information on startup failures related to mixing incorrect versions of 
DIMMs, see the chart on page 2 of this chapter.
Power-on LED does not illuminate when power button is pressed, fans do not 
spin, and there is no boot tone or video
1. Verify power outlet is good
2. Replace power cord
3. Reset the logic board. Refer to “Resetting the Logic Board” in this chapter.
4. Verify power supply cables are fully connected
5. Check for trickle voltage on the power supply connector. Refer to “Power Supply  Ve r ification” in this chapter. If veri fication fails, replace power supply.
6. Reseat front panel board cable
7. Replace front panel board cable
8. 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 9. Otherwise, go to step 12. 
						

							
Power Mac G5 (Late 2004) Troubleshooting - 9
 Symptom Charts 9. 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 10. Otherwise, go to step 11.
10. Replace front panel board
11. Replace power button
12. Replace logic board
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
1. Reseat video card. (Make sure video card is fully inserted in connector and end of  card is secured by the connector latch.)
2. Reset the logic board. Refer to “Resetting the Logic Board” in this chapter.
3. Verify power supply cables are fully connected
4. Check for trickle voltage on the power supply connector. Refer to “Power Supply  Ve r ification” in this chapter. If veri fication fails, replace power supply.
5. Replace logic board
Power-on LED illuminates when power button is pressed and fans spin 
continuously but there is no boot tone or video
1. Reseat video card. (Make sure video card is fully inserted in connector and end of  card is secured by the connector latch.)
2. Verify speaker cable is fully seated.
3. Reset the logic board. Refer to “Resetting the Logic Board” in this chapter.
4. Replace logic board
Power-on LED illuminates when power button is pressed, fans spin, and boot 
tone chimes, but there is no video
1. Reseat video card. (Make sure video card is fully inserted in connector and end of  card is secured by the connector latch.)
2. Reset PRAM (restart computer while holding down Control-Option-P-R keys until  second boot tone chimes)
3. Replace video card
4. Reset the logic board. Refer to “Resetting the Logic Board” in this chapter.
5. Replace logic board