Apple power mac g4 mirrored drive doors 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  board. The fabrication number is easily visible at the edge of the board near PCI card 
slot 5.
2. If the logic board fabrication number is 820-1308, 820-1440, or 820-1445, do   
not
 
 
order the processor module. Instead, you must replace both the logic board and the 
processor by ordering the combined module: Module Set, Logic and Processor (Apple 
part number 661-3691).  
Replacement Warning:  
 When ordering this combined module set, a returned logic 
board must match one of the three fabrication numbers (820-1308, 820-14\
40, or 820-
1445). If the logic board does not match one of these fabrication numbe\
rs, it will be 
rejected.
3. If the logic board fabrication number is any other number (  
not 
 
820-1308, 820-1440, or 
820-1445), order only the multiprocessor module (Apple part number 661-2711). 
						

							
 
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 
Presence Detect2
4 DDR SDRAM
DIMM Slots
Up to 2048MB
using Industry Standard
512MB DIMMs
100/200/400/800 Mbps PHY10/100/GbBaseT PHY125 MHz, 8bit
Phy Powered Whenever
AC Power Available
1394a1394a FireWire
Rear of
Enclosure
Port
Power
(25V, 15W )
RI-45
1024kB ROM Contains:
•Open Firmware •Hardware INIT •POST PCI Bus (PCI 1) 33 MHz 64bitAGP-4 Bus (PCI 0) 66/133/266MHz, 32bit
KeyLargo
I/O Controller
Interrupt Controller
PCMCIA
E-IDE
ATA(PI)Ultra
DMA66I  S
Audio2USB #2USB#1DAV
AudioSerialSPI
Pwr
Mgr99 •Sleep
•Power  On/Off
•Power  LED•I  C
2
AP
Equalizer
Codec
AmplifiersStereo
L1
LC
HP Stereo
Stereo
Mono
StereoTo
AGP
Comm Slot
POTS Modem
Unused
5V Sleep
Rear of Enclosure
RJ-11 AirPort
Slot
AirPort
Module
Cable
Selects
Master/ Slave
SuperDrive DVD-R, CD-R or Combo DVD, CD-R
5V Tolerant
33MHz, 64bit PCI Slots
PCI Bus (PCI 1) 33MHz 64 bit
USB
1.5V AGP Slot
25VADC Monitor Power and Control
2
Rear Panel
1/8" Line In and Line Out
Connectors
Front Panel
1/8" Headphone Jack and
Mono Speaker
Rear PanelApple Pro
Speakers II w Eq ROM Serial ROM 
5V
Sleep 3.3V
Sleep 
						

							
 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 handling the logic board. The PMU is very sensitive and 
touching the circuitry on the logic board can cause the PMU to crash. If the PMU crashes 
and is not reset, the battery life goes from about  five years to about two days.
 
Note:  
 For the location of the PMU reset button, see “Logic Board Diagram”\
 in the Views 
chapter.
Many system problems can be resolved by resetting the PMU chip. When you have a 
computer that fails to power up, follow this procedure before replacing any modules: 
1. Disconnect the power cord and check the battery in the battery holder. The battery  should read 3.3 to 3.7 volts. If the battery is bad, replace it, wait ten seconds, and then 
proceed to step 2. If the battery is good, go directly to step 2.
2. Press the PMU reset button once and then proceed to step 3. Do not press the PMU  reset button a second time because it could crash the PMU chip.
3. Wait ten seconds before connecting the power cord and powering on the computer. If  the computer does not power on, there is something else wrong with it; refer to the 
“System” section of “Symptom Charts” in this chapter.  
Note:  
  The above procedure resets the computer’s PRAM. After resetting the PMU, be 
sure to reset the time, date, and other system parameter settings. 
						

							
 
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 plugged into its 
connector on the logic board.
The following  figure shows the pins and voltage on the computer’s power supply 
connector. (The color noted represents the color of the wire attached to the pin.\
) 
  
1. Plug a known-good power cord into the computer. Do not turn on the computer.
2. Connect the black lead of the volt meter to pin 12 of the power supply connector;  connect the red lead of the volt meter to pin 14. The volt meter should measure 
approximately +25V.
If you do not get a reading of +25V, recheck the volt meter connections \
and measure 
the voltage again. If voltage is still not present, replace the power su\
pply.
If you do measure +25V on pin 14, the power supply is likely OK. Go to t\
he next step 
for further verification.
3. Check the trickle voltage by connecting the black lead of the volt meter to pin 12 of the  power supply connector; connect the red lead of the volt meter to pin 1. The volt meter 
should measure approximately +5V.
If you do not get a reading of +5V, recheck the volt meter connections a\
nd measure 
Pin 23 GND Black
Pin 22+12V Yellow
Pin 21+12V Yellow
Pin 20GND Black
Pin 19+3.3V Orange
Pin 18+3.3V Orange
Pin 17+3.3V Orange
Pin 16GND Black
Pin 15+5V Red
Pin 14+25V Standby White
Pin 13GND Black
Green Power OnPin 11
Yellow +12VPin 10 Black GNDPin 9Blue -12VPin 8
Black GNDPin 7
Orange +3.3V Pin 6 Black GNDPin 5Red +5VPin 4
Red +5VPin 3
Black GND Pin 2
Purple +5V TRKL StandbyPin 1
Pin 24 +12V  Yellow
Black GND Pin 12 
						

							
 
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 fan is spinning. If the fan is not spinning, replace the power supply. If the fan is spin\
ning, go to the 
next step.
6. Connect the black lead of the volt meter to pin 12 of the power supply connector;  connect the red lead of the volt meter to pin 24. 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 su\
pply.
If you do measure +12V on pin 24, the power supply is likely OK. Go to t\
he next step 
for further verification.
7. Connect the black lead of the volt meter to pin 12 of the power supply connector;  connect the red lead to pin 6. The volt meter should measure approximately +3.3V.
If you do not get a reading of +3.3V, recheck the volt meter connections\
 and measure 
the voltage again. If voltage is still not present, replace the power su\
pply.
If you do measure +3.3V on pin 6, the power supply is likely OK. Go to t\
he next step 
for further verification.
8. Connect the black lead of the volt meter to pin 12 of the power supply connector;  connect the red lead to pin 3. The volt meter should measure approximately +5V.
If you do not get a reading of +5V, recheck the volt meter connections a\
nd measure 
the voltage again. If voltage is still not present, replace the power su\
pply.
If you do measure +5V on pin 3, the power supply is likely OK. Go to the\
 next step for 
further verification.
9. Connect the black lead of the volt meter to pin 12 of the power supply connector;  connect the red lead to pin 10. 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 su\
pply.
If you do measure +12V on pin 10, the power supply is OK and the testing\
 is 
complete. You have verified that the power supply is not the cause of th\
e “no 
apparent power” symptom. 
						

							
 
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:   
Incompatible RAM types are installed.
•  
3 beeps:   
No RAM banks passed memory testing. 
•  
4 beeps:   
No good boot images are detected in the boot ROM (and/or there is a bad\
 
sys config block).
•  
5 beeps:   
The processor is not usable. 
						

							
 
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 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.  
Using Classic in Mac OS X
 
Important:  
  The Power Mac G4 (FW 800) computer starts up only in Mac OS X. Mac OS 
9 is not available as a startup disk and previous versions of the Mac OS should not be 
installed on this computer.
However, in addition to using Mac OS X applications, you can continue to use most Mac 
OS 9 applications in the Classic environment. Classic works in the background to access 
Mac OS 9 features and software applications. When you start up Classic, Mac OS 9 
software works in Mac OS X just as it did in Mac OS 9, but does not bene fit from Mac OS 
X features such as the look of the new interface. To use Classic, open the Classic pane of 
System Preferences and click Start. You can also open a Mac OS 9 application or double-
click a document that requires a Mac OS 9 application. If Classic is not running, it starts 
up. 
						

							
 
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 this chapter. If veri fication fails, replace the power supply.
6. Disconnect external devices, including the monitor, and start up the computer.
7. Remove internal cards and start up the computer.
8. Disconnect internal hard drives from the logic board and start up the computer.
9. Check the modem connector. If the connector has any bent pins, replace the logic  board.
10. Check the pins in the power supply connector on the logic board. If the pins are bent,  replace the logic board.
11. Replace the logic board. 
Memory error message appears on the screen
 
1. Reseat the DIMMs. 
2. Verify that only the correct SDRAM DIMMs are installed. 
3. Replace the DIMMs one at a time and test until all bad DIMMs are replace\
d with  known-good modules. 
Flashing question mark appears on the screen
 
1. Start up from the system restore CD and check to see if the hard drive shows up in the  Disk Utility. If it does, go to step 2. If it does not, go to step 4.
2. Run Disk Utility. Update the driver and restart the computer.
3. Reinstall system software using the system restore CD that came with the computer.
4. If you are starting up in Mac OS 9, turn off your Mac OS 9 system extensions: • Start up the computer while holding down the Shift key.
• If the computer is set to start up from another computer on your network\
, check that the Ethernet cables are firmly connected, then restart the computer\
. If the 
computer has trouble connecting to the network, check that the startup c\
omputer or 
server is not down. 
						

							
 
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 information in the\
 onscreen  help. Choose Mac Help from the Help menu. Look at the section on how to \
prevent 
and solve problems. You may need to check for extension conflicts or rei\
nstall the 
computer’s system software.
5. Reseat the hard drive data and power cables.
6. Replace the hard drive. 
Computer begins to power up, the fan and hard drive are spinning, the power 
LED is lit (or the LED goes off when button is no longer pressed), but there is 
no startup chime or video
 
1. Reset the logic board. Refer to “Resetting the PMU on the Logic Board” in this  chapter.
2. Verify all PCI and AGP cards are seated properly.
3. Reseat the processor module.
4. Replace the processor module. Refer to Before Replacing the Processor in this  chapter.
5. Replace the logic board. 
Power Mac G4 (Mirrored Drive Doors) model starts up and runs properly, 
but fan spins constantly at high speed
 
1. Verify that the fan is spinning at full speed as soon as the computer is turned on, and  that it stays at high speed until it is turned off.
2. Verify that the computer starts up and functions normally.
3. Check the logic board number printed near the modem connector, just under the  words Apple Computer, Inc. If this number is 820-1308, replace the logic board.   
Note:  
 Service stock no longer contains 820-1308 logic boards. 
No image on screen
 
1. Make sure the display and computer are turned on.
2. Make sure the cables are connected properly to the computer and display.
3. If an ADC display is connected, check the ADC connectors on the video card and the  cable for physical damage. If the video card connector looks  fine, test for the symptom 
with a known-good display.
4. Make sure the computer is not in sleep. Press the power button or any key to see if the  
						

							
 
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 turned on and the correct voltage is present.
4. Replace the power cord.
5. Make sure the air vents are clear. 
6. Check that the fan cables are connected and the fans are operational. 
7. Check that the heatsink is properly attached to the processor.
8. Reset the logic board. Refer to “Resetting the PMU on the Logic Board” in this  chapter.
9. Replace the power supply.
10. Replace the logic board. 
System shuts down almost immediately after startup
 
1. Reset the logic board. Refer to Resetting the PMU on the Logic Board in this  chapter.
2. Disconnect the power cables to all hard drives and optical drives. Remove all cards  and test power sequentially to troubleshoot cards and drives.
3. Check the modem connector. If the connector has any bent pins, replace the logic  board. 
4. Replace the processor module. Refer to Before Replacing the Processor in this  chapter.
5. Replace the power supply.
6. Replace the logic board.