User Guide

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 rmware 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 dierent PCI slot.•
Try a dierent graphics card. •
If an error message about graphic card booster power connection is displayed, check that •
the appropriate booster power cable is rmly 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