User Guide

Mac Pro (8x) Troubleshooting — General Information 14 4
Replace the video card.•
Ext_Power LED
Normally o, 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 dierent auxiliary power cable. •
Try a dierent video card. •
Replace the video card.•
Power Supply Verication
To power on, the computer’s logic board requires “trickle” power. If the system fails to power on,
rst 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 ash
memory, that will hold the software code indenitely, 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 rmware is stored on the Mac Pro (8x) logic board. EFI rmware updates update