Apple power mac g4 fw 800 User Manual

 Power Mac G4 (Mirror/FW800) Troubleshooting - 
 
7
 
 General Information 
Before Replacing the Processor
 
Important:  
 Apple has determined a compatibility issue between the processor and certain 
fabrication levels of the logic board on some Power Mac Server G4 (Mirrored Drive Doors) 
and Power Mac G4 (Mirrored Drive Doors) products. Before ordering a replacement 
processor for those models, follow these steps:
1. Open the computer and check the fabrication number that is printed on the logic...

 
8 -   
Power Mac G4 (Mirror/FW800) Troubleshooting  General Information 
Block Diagram
Backside L3 Cache
2MB SRAM(Dual)
Backside L3 Cache
2MB SRAM
1.2 Cache256KB
PowerPC  ApolloCPU Module
MaxBus
133 MHz
4.1 u P-I3
1.2 Cache256KB
PowerPC  Apollo (Dual)
I  C
ROM
MaxBus/60x Bus Interface
133 MHz, 64 bit
Main
Memory
133 MHz, 64 bit
AGP-4x
Interface
66/133/266 MHz
32 bit
ATA 100
Interface
Gigabit
Ethernet
FireWire
100/200/400
800 Mbps
PCI
Interface
33MHz, 64 bit
Uni
Fan
Controller
12V Main
I   C for Serial...

 Power Mac G4 (Mirror/FW800) Troubleshooting - 
 
9
 
 General Information 
Resetting the PMU on the Logic Board
 
The PMU (Power Management Unit) is a microcontroller chip that controls all power 
functions for this computer. The PMU is a computer within a computer. Its function is to: 
• tell the computer to turn on, turn off, sleep, wake, idle, etc.
• manage system resets from various commands.
• maintain parameter RAM (PRAM).
• manage the real-time clock.  
Important:  
 Be very careful when...

 
10 -   
Power Mac G4 (Mirror/FW800) Troubleshooting  General Information 
Power Supply Verification
 
To power on, the computer’s 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. When connecting the volt meter 
leads to speci fic pins, make sure the power supply remains securely...

 
Power Mac G4 (Mirror/FW800) Troubleshooting -   
11
 
 General Information the voltage again. If voltage is still not present, replace the power su\
pply.
If you do measure +5V on pin 1, the power supply is likely OK. Go to the\
 next step for 
further verification.
4. Start up the computer by pressing the power button on the front panel. If the computer starts up normally, the power supply is OK. If the compu\
ter does not 
start up normally, go to the next step.
5. Check to see if the power supply...

 
12 -   
Power Mac G4 (Mirror/FW800) Troubleshooting  General Information 
RAM and Processor Verification: 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, you will not hear a normal startup chime. Instead, 
the system will beep as explained below:
•  
1 beep:  
 No RAM is installed or detected.
•  
2 beeps:...

 
Power Mac G4 (Mirror/FW800) Troubleshooting -   
13
 
 Symptom Charts 
Symptom Charts
 
How to Use the Symptom Charts
 
The Symptom Charts included in this chapter will help you diagnose speci fic 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...

 
14 -   
Power Mac G4 (Mirror/FW800) Troubleshooting  Symptom Charts 
Startup
 
System is completely dead (no fan movement and power LED is not lit)
 
1. 
Verify the power outlet is good. 
2. Replace the power cord. 
3. Make sure the voltage switch on the back of the power supply is set to the correct  voltage.
4. Reset the logic board. Refer to “Resetting the PMU on the Logic Board” in this  chapter.
5. Check for trickle voltage on the power supply connector. Refer to “Power Supply  Ve r ification” in...

 
Power Mac G4 (Mirror/FW800) Troubleshooting -   
15
 
 Symptom Charts • If in Mac OS 9, remove any items from the Servers folder in the System F\
older.
If that does not work, of if you are starting up in Mac OS X, turn off t\
he computer by 
holding down the power button. Then start up using the Software Install \
CD.
• Insert the system software CD and start up while holding down the C key.\
 (Make 
sure the Caps Lock key is not engaged.)
• After the computer starts up, see the troubleshooting...

 
16 -   
Power Mac G4 (Mirror/FW800) Troubleshooting  Symptom Charts
computer wakes.
5. Make sure the display brightness and contrast are set properly. 
6. Reset the PRAM by restarting the computer while holding down the Command,  Option, P, and R keys until you hear the startup sound a second time. Then start up 
using the Software Install CD. 
System shuts down intermittently
 
1. Make sure the power cord is plugged in  firmly.
2. Check the Energy Saver settings.
3. Check that the power source is...