Apple mac pro 8x User Manual

							Mac Pro (8x) Troubleshooting — General Information 141
LED 2 CPU B (Lower Processor) Error 
LED 3 CPU A (Upper Processor) Error
Normally off. These LEDs come on if an error occurs or if the BootROM is corrupted. They do not 
depend on the DIAG_LED button being pressed.
Related symptoms include no video or the computer is hung up. If the BootROM is corrupted, 
the optical drive tray should eject, prompting for the insertion of a recovery disc to restore the 
BootROM.
Troubleshooting: 
With the computer booted, up press the SYS_RST switch. If this clears the CPU Error LED, • 
check for incompatible device driver software that may have been installed for added 
hardware. 
If the Error LED is still on, power down the computer and try pressing the SMC_RST switch. • 
Restart the computer.
Reset the power supply by unplugging the AC cord for 10 seconds.• 
Unplug AC cord and remove any added DIMMs and PCI Express cards. If this causes the • 
LED to go off, repopulate the DIMMs and/or PCI Express cards to find the combination that 
caused the LED to come on. Overheated memory could be a possible cause for this CPU 
error LED to come on. Check fan operation.
Unplug the AC cord and remove the battery for 10 seconds. You may need to remove a PCI • 
Express card to get to the battery. Reinstall the battery and restart the computer.
Try swapping CPU A and CPU B locations. If the CPU Error LED follows the CPU, replace that • 
CPU. 
Try replacing the logic board.• 
LED 4 CPU B (Lower Processor) Overtemp
LED 5 CPU A (Upper Processor) Overtemp
Normally off. These LEDs come on if an error occurs. They do not depend on the DIAG_LED 
button being pressed. 
These two LEDs can operate in two different modes; they will either flash or stay on. If either 
LED is flashing, it may indicate an initial processor over-temperature condition. If either LED is 
solidly on, it may indicate a chronic processor over-temperature condition. Initial processor over-
temperature can cause symptoms such as sluggish computer performance. Chronic processor 
over-temperature can cause the computer to hang completely.
Troubleshooting: 
Verify proper heatsink installation. • 
Verify all thermal sensors are properly connected. • 
Verify all fans are operating properly, especially the front intake fan.• 
Verify power supply cables are properly seated. • 
If both overtemp LEDs come on immediately when the computer is turned on, a faulty • 
power supply could be one cause of this behavior. Replace power supply.
Try swapping CPU A and CPU B heatsink locations. If the CPU Error LED follows the CPU • 
heatsink, replace that CPU heatsink. 
						

							Mac Pro (8x) Troubleshooting — General Information 142
Try swapping CPU A and CPU B locations. If the CPU Error LED follows the CPU, replace that • 
CPU.
LED 6 GPU Present
Normally on when DIAG_LED button is pressed. 
If this LED is on, it indicates there is a graphics card installed and recognized by the computer. 
It does not indicate that the graphics card is fully functional. Some graphics cards require 
additional power to function, which is available from connectors on the logic board. For these 
cards, if the auxiliary booster power cable is not connected between the logic board and the 
graphics card, an error message reminding about this additional power connection will be 
displayed as Mac OS X starts up.
Troubleshooting: 
Check that the graphics card is seated correctly in its PCI slot. • 
Check that the card’s auxiliary booster power cable is connected properly on both ends • 
(if the card requires one). If the cable is connected properly, try connecting it to the other, 
empty logic board booster power connector (if available) to see if the cause is related to 
this connector. If the card and LED operate properly when connected to the other power 
connector, check EFI and SMC firmware versions and update them if necessary. See “Mac 
Pro Firmware Updates” in this section for more information. Only then should you consider 
replacing the logic board.
Verify power supply cables are properly seated• .
Try the graphics card in a different PCI slot.• 
Try a different graphics card. • 
If an error message about graphic card booster power connection is displayed, check that • 
the appropriate booster power cable is firmly connected between the logic board and the 
graphics card.
Replace the logic board. • 
LED 7 Power On
Normally on when DIAG_LED button is pressed. 
If this LED is on, it indicates the power supply is functioning. 
Troubleshooting: 
Check that the power cables to the logic board  are properly attached. • 
Check the cable connections at the power supply. • 
Check for any signs of an obvious electrical short, e.g. metal screws or PCI card slot cover • 
loose inside computer touching the logic board.
LED 8 EFI Good
Normally on when DIAG_LED button is pressed. Takes approximately 5 seconds after power up.
If this LED is on, it indicates that the computer has completed the on board Extensible Firmware  
						

							Mac Pro (8x) Troubleshooting — General Information 143
Interface (EFI) operations and the operating system is now in control. 
Troubleshooting: 
Check that LED 7 Power On LED is on. • 
Check that LEDs 2, 3, 4, and 5 are off. • 
Try removing any added hardware. • 
Try removing any added DIMMs. • 
Memory Riser Card Diagnostic LEDs
Both of the memory riser cards include diagnostic LEDs for each DIMM. Each of the LEDs will 
light if it detects an issue with the corresponding installed DIMM. These LEDs will also flash briefly 
when the computer is started up or shut down and when it goes in and out of sleep mode. This 
is normal behavior.
Troubleshooting: 
Shutdown and restart the computer. • 
Verify EFI and SMC firmware versions and update them if necessary.  See “• Mac Pro Firmware 
Updates” in this section for more information.
Reseat the memory riser card associated with the failure LED.  If the failure LED persists, • 
continue with the next step.
Swap upper and lower memory riser cards A and B.  If the symptoms follow the riser card, • 
continue with the next step.  If the failure LED remains associated with the same memory 
riser card slot, consider a possible connection issue with the logic board.  Replace the logic 
board in this case.
Reseat the appropriate DIMM corresponding to the failure LED.  If the issue persists, continue • 
with the next step.
Check memory installation instructions for proper installation order. • 
Swap affected DIMM with known good DIMM.• 
Try moving DIMM to another slot (within the same bank of two) to see if the failure LED • 
follows the DIMM. If so, replace DIMM with known good DIMM. If the failure LED persists, 
replace the memory riser card associated with the failure LED.
Video Card Diagnostic LEDs
T_Fault LED
Normally off, this LED lights up if the graphics chip gets too hot.
Troubleshooting: 
Verify that the video card heatsink and fan are not clogged with dust. Carefully blow out any • 
dust as necessary.
Check that the front fan is working. • 
Try re-seating the card in the PCI Slot. • 
Make sure the card’s auxiliary booster power cable is connected (if there is one). • 
Re-boot the computer. • 
Try a different video card. •  
						

							Mac Pro (8x) Troubleshooting — General Information 14 4
Replace the video card.• 
Ext_Power LED
Normally off, this LED lights up if the auxiliary power isn’t being supplied.
Troubleshooting: 
Make sure the card’s auxiliary booster power cable is connected (if there is one). • 
Check connections from the power supply to the logic board. • 
Try a different auxiliary power cable. • 
Try a different video card. • 
Replace the video card.• 
Power Supply Verification 
To power on, the computer’s logic board requires “trickle” power. If the system fails to power on, 
first reset the SMC as described in this chapter. If the computer still doesn’t power on, follow the 
procedure outlined below to determine whether the issue is related to the power supply.
Verify trickle power 
Diagnostic LED 1 indicates the presence of trickle power required by the logic board to begin the 
startup process. 
LED 1 should be yellow when the DIAG_ LED button is pressed, indicating that trickle voltage is 
present.
Verify Power Supply Is Providing Power 
Diagnostic LED 7 indicates that the main power is OK and within regulation. 
Plug in AC power cord, and press the power-on button on the front panel. 
LED 7 should be green when the DIAG_ LED button is pressed, indicating that the main power is 
OK and within regulation.
If diagnostic LED 4 and LED 5 are both solidly illuminated at power up, improperly seated power 
supply cables could be one cause of this behavior. Check all power supply cable connections to 
ensure they are properly seated.
Mac Pro Firmware Updates
Firmware is the name given to software that is written into memory circuits, such as flash 
memory, that will hold the software code indefinitely, even when power is removed from the 
hardware. Firmware on Intel Mac computers is designed to be updated if necessary through a 
software update.
EFI and SMC firmware is stored on the Mac Pro (8x) logic board. EFI firmware updates update  
						

							Mac Pro (8x) Troubleshooting — General Information 145
the Boot ROM, and SMC updates update the System Management Controller firmware. The SMC 
manages fans and other environmental parameters that are independent of the Boot ROM.
Firmware symptoms can be easily mistaken for hardware issues (e.g., overheating issues, fan 
noise issues, etc.). Always check both EFI and SMC firmware versions and update if necessary 
before replacing any hardware components in the Mac Pro (8x).
The following lists describe the type of symptoms that may be resolved by updating the EFI and 
SMC firmware in the Mac Pro (8x).
Symptoms that may be resolved by updating EFI firmware:
Cannot eject media (various conditions)• 
No video on start up• 
Blue system failure screens in Windows XP/Vista• 
Not waking or sleeping when expected• 
Bad media taking too long to eject (including holding mouse button down at startup taking • 
minutes to eject)
Symptoms that may be resolved by updating SMC firmware:
Fan related behavior (excessive speed or noise)• 
Loud audible clicking from some fans• 
Thermal shut down or warnings• 
Diagnostics reporting failures• 
Sleep/wake issues• 
Intermittent shut down• 
SMC causes bad/missing ambient sensor to cause the computer to go to sleep• 
Hangs, black screen on restart from Windows• 
Quick power cycle causes Memory Riser Card Diagnostic LEDs & CPU Overtemp LEDs to • 
illuminate solidly
Unit does not restart after changing configuration in Expansion Slot Utility• 
Please follow the steps outlined in KnowledgeBase article 303364, “About Firmware Updates for 
Intel-based Macs,” to perform an EFI and/or SMC firmware update. Information about firmware 
versions for Intel Macs can be found in KnowledgeBase article 303880, “Mac OS X: Firmware 
Updates for Intel-based Macs.” 
						

							Mac Pro (8x) Troubleshooting — General Information 146
Processor Heatsink and Processor Visual Inspection Instructions
The Mac Pro (8x) uses a special coating on the processor heatsink and processor to manage the 
temperature in the computer. Before installing a new or existing heatsink or processor, always 
make a visual inspection of the part. Specifically, check the application of the silver-colored 
coating on the underside of the heatsink and the top of the processor. In addition, check the 
condition of the gasket that surrounds the coating on the heatsink.
Important: When inspecting the special coating, wear disposable nitrile or latex gloves and avoid 
touching the coating. 
Silver-Colored Coating on Heatsink and Processor
Use the following guidelines to determine if the silver-colored coating on the underside of the 
heatsink and the top of the processor is correctly applied. If a new, replacement heatsink or 
processor fails to meet the prescribed standards, return it to Apple. If an existing heatsink or 
processor fails the standards, replace it with a new part before installing it in the computer.
Acceptable standard
The silver-colored coating should be applied in a smooth, even square as show below. 
						

							Mac Pro (8x) Troubleshooting — General Information 14 7
Unacceptable examples
The following are examples of unacceptable applications of the coating. Return new parts or 
replace existing parts that exhibit similar applications. 
Void IVoid IISplash
Void I: The silver-colored coating shows missing areas of within the normal coated area.
Void II: The silver-colored coating shows missing areas along the edge of the coated area.
Splash: The silver-colored coating extends beyond the normal coated area.
Important: If you observe a heatsink or processor with a “splash” of special coating, first try to 
remove the excess by using the method described below under “Removing Stray Particles of 
Coating.” If this approach does not remove the splash, return the part to Apple.
Removing Stray Particles of Coating
In rare cases, small particles or beads of the silver-colored coating may appear outside the normal 
coated area of a replacement heatsink or processor. You must remove these particles before 
installing the part. Failure to do so could result in damage to the part or the logic board. 
						

							Mac Pro (8x) Troubleshooting — General Information 14 8
To remove the particles, use the suction pipette that comes with the replacement heatsink and 
processor. ( The pipette is also available through GSX as part of the Mac Pro Grease Kit, part 
number 076-1258.) Depress the bulb end of the pipette, place the other end over the particle, 
and release the bulb. The particle will be suctioned into the pipette. 
Once you have removed all stray particles, place the pipette inside the resealable bag included 
with the replacement part. Pack this bag along with the failed part in the box that the 
replacement part came in, and return the box to Apple.
Gasket on Heatsink
Check that the gasket that surrounds the silver-colored coating on the underside of the heatsink 
is in good condition, as shown below.
Replace the gasket if it shows obvious damage, such as cracks, folds, and broken-off surfaces, or 
if it is dislocated from the heatsink. The gasket is available through GSX as part of the Mac Pro 
Grease Kit, part number 076-1258. 
						

							Mac Pro (8x) Troubleshooting — Symptom Charts 149
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: Be sure to check the “Memory” and “Power-On Self Test” topics in the General Information 
section of this chapter. Incorrect installation of DIMMs or incompatible memory will not allow the 
system to start up correctly. For information on how to correctly install DIMMs, see the “Memory 
(DIMMs)” topic in the Take Apart chapter. 
Important: For troubleshooting purposes, Mac Pro (8x) computers may be started up and 
diagnosed with a single processor installed in either the upper (CPU A) or lower (CPU B) position.
Power-on LED does not illuminate when power button is pressed, fans do not 
spin, and there is no boot tone or video 
Verify power outlet is good. 1. 
Check that diagnostic LED 1 is on when the power cord is connected.2.  
Replace power cord. 3. 
Check that diagnostic LED 1 is on when the power cord is connected.4. 
Reset the logic board. Refer to “5. Resetting the Logic Board” in this chapter. 
Verify power supply cables are fully connected. 6. 
Verify that processors are properly seated. Check diagnostic LED 2 and/or LED 3. 7.  
						

							Mac Pro (8x) Troubleshooting — Symptom Charts 150
Verify that processors’ mounting clamps are properly tightened. 8. 
Test whether the front panel board or power button is at fault. Remove the installed front 9. 
panel board and test with a known-good front panel board. 
Replace front panel board. 10.  
Replace power button. 11 . 
Replace power supply. 12.  
Replace logic board. 13 . 
Power-on LED illuminates when pressed in, but goes out when button is released, 
there is no boot tone or video, but you can hear a small click 
Check diagnostic LED 1 for trickle voltage from the power supply. Refer to “1. Power Supply 
Verification” in this chapter. If verification fails, replace power supply. 
Verify that the processors are properly seated. Check diagnostic LED 2 and/or LED 3. 2.  
Verify that the processor mounting clamps are properly tightened. 3. 
Replace the power supply.4. 
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 1. 
secured by the connector latch.) For video cards that require power cables, check that they 
are connected. 
Reset logic board. Refer to “2.  Resetting the Logic Board” in this chapter. 
Verify power supply cables are fully connected. 3. 
Check diagnostic LED 2 and/or LED 3 for processor connection. 4. 
Reseat processors and check for bent pins. 5. 
Check diagnostic LED 1 for trickle voltage from the power supply. Refer to “6. Power Supply 
Verification” in this chapter. If verification fails, replace power supply. 
Replace logic board. 7. 
Replace processor. 8.  
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 1. 
secured by the connector latch.) For video cards that require power cables, check that they 
are connected. 
Verify speaker cable is fully seated. 2.  
Reset logic board. Refer to “3. Resetting the Logic Board” in this chapter.