User Guide
Mac Pro Troubleshooting — Symptom Charts 155
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
Verication” in this chapter. If verication 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.
Verify power supply cables are properly seated4. .
Replace the power supply.5.
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 properly seated3. .
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
Verication” in this chapter. If verication 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.