Apple power mac g4 gigabit ethernet User Manual

 
 TroubleshootingGeneral/Block Diagrams -  3 
Power Mac G4 (AGP Graphics) Block Diagram
100 MHz
memory bus100 MHz
Max bus
Microphone jack
Headphone jack Ethernet port Firewire port
Firewire port 32-bit
66 MHz
PCI busAGP
2x slot AGP 2x bus
PCI slots
64-bit
33 MHz
PCI bus
Backside
L2 cachePowerPC G4
microprocessor
UniNorth
memory
controller
and PCI
bus bridge
PMU99
power
controller
Boot
ROM
Ethernet
PHY
Firewire
PHY
Ethernet
controller
Firewire
controller
Screamer
sound IC
Modem slot...

 
 TroubleshootingGeneral/Block Diagrams -  4 
Power Macintosh G4 (PCI Graphics) Block Diagram 

 
 TroubleshootingGeneral/Power-On Self Test  -   5 
Power-On Self Test 
There is a power-on self test that resides in the ROM of the Power 
Mac G4. This test automatically runs whenever the computer is 
powered on after being fully shut down (the power-on self test 
does not run if the machine is only restarted). If a problem is 
detected during the test, you will not hear a normal startup chime. 
Instead, the system will beep as explained below.
Power Mac G4 (all models except PCI Graphics):
¥ 
1 Beep:...

 
 TroubleshootingGeneral/Power-On Self Test  -   6 
Power Macintosh G4 (PCI Graphics):
¥ 
1 Beep: 
 No RAM is installed or detected.
¥ 
2 Beeps:  
Incompatible RAM types are installed (for example, 
both SDRAM and EDO installed).
¥ 
3 Beeps:  
No RAM banks passed memory testing. 
¥ 
4 or 5 Beeps:  
Bad checksum for the remainder of the boot ROM 
block. The ROM is bad and probably cannot be fixed. 

 
 TroubleshootingGeneral/ Logic Board Diagrams  -   7 
Logic Board Diagrams 
Power Mac G4 (QuickSilvers/Digital Audio) 
Logic Board Diagram
Battery PCI 
Slots
Power
FireWire 
Ports (2) USB 
Ports
A &  B
Ethernet 
Connector SDRAM
DIMM 
Slots
 SpeakerPMU Button Ultra ATA
Connector
Modem
Connector
Front Panel
Board
AirPort
ConnectorMonitor 
Card 
Slot
IDE
Connector
Single or Dual
Processor Digital Audio  Jack
Headphone Jack 

 
 TroubleshootingGeneral/ Logic Board Diagrams  -   8 
Power Mac G4 (AGP Graphics/Gigabit Ethernet) 
Logic Board Diagram
BatteryPCI Slots
Power
FireWire 
Ports (2)
Internal
FireWire 
Por t
(not included
on Gigabit
models) USB 
Ports
A & BEthernet 
Connector
SDRAM
DIMM Slots  Speaker PMU Button
Ultra ATA
Connector
Modem 
Connector

Front Panel
Board
AirPort
ConnectorMonitor 
Card Slot
IDE
Connector
Processor
Plug-In
Slot
Sound In
Sound Out 

 
 TroubleshootingGeneral/ Logic Board Diagrams  -   9 
Power Macintosh G4 (PCI Graphics) Logic Board Diagram
J1 ATA-3
(CD/DVD-ROM 
and Zip Drive
J15 Ultra DMA/33
(ATA Drives)
J23 Power
Battery S5 Power Button
S4 Cuda Button
J8 CD Audio
J31
Front Panel
BoardProcessor
Plug-In
SlotJ34
 SpeakerJ25
Jumper Block 
(w/sticker)J2 Firewire
Power SDRAM
DIMM Slots Modem 
Connector

USB 
Ports
A & B Sound In & 
Sound Out
Por ts Monitor Card Slot
PCI Slots
Ethernet Connector
Firewire Ports (2)...

 
 TroubleshootingGeneral/Logic Board Troubleshooting  -   1 0 
Logic Board Troubleshooting 
Power Mac G4 (all models except PCI Graphics) 
Processor Module 
The logic board comes with a removable processor module. The 
processor should rarely fail and should be replaced only as a last 
resort. Processor modules can be ordered from Service.
Refer to ÒProcessor ModuleÓ in the Take Apart chapter for more 
information. 
Resetting the PMU on the Logic Board 
The PMU (Power Management Unit) is a...

 
 TroubleshootingGeneral/Logic Board Troubleshooting  -   1 1 
I/O, two crystals, and a CPU. 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 handling the main logic board. 
Remove the battery when handling the logic board so the PMU is 
not affected. The PMU is  
very 
 sensitive and touching the circuitry 
on the...

 
 TroubleshootingGeneral/Logic Board Troubleshooting  -   1 2 
procedure before replacing any modules: 
1. Disconnect the power cord and check the battery in the battery 
holder (BT1). The battery should read 3.3 to 3.7 volts. If the 
battery is bad, replace the battery, wait ten seconds, and then 
reset the PMU (refer to the next step). If the battery is good, 
go to the next step.
2. Press the PMU reset switch (S1) once on the logic board and 
then proceed to step 3. Do  
NOT 
 press the PMU reset...