Mac pro 5.1 cpu a and cpu b red leds manual#
Mac pro 5.1 cpu a and cpu b red leds mac#

PSU PWROK (green), 5V STBY (amber), EFI DONE (green), GPU OK (green) LEDs illuminatedĪt this point, to make testing easier try powering on the computer using a known good front panel board, power button, and cable, instead of jumpering SYS_PWR solder pads.ĩ.

To help troubleshoot processor issues, check the related CPU Error LED.

The solder pads are at the same location where the power button would be.

One red-colored error LED illuminates on the processor board (next to the memory slots).

Front and rear processor cage fans (and PCIe fan, if installed) should spin slowly.

Mac pro 5.1 cpu a and cpu b red leds mac#

Momentarily jump the SYS_PWR solder pads to turn ON the Mac Pro. If the LED does not illuminate, suspect power supply or backplane board failure.Ħ. This is a verify step, as you’ve added modules since previous step.ĥV STBY LED illuminates, confirming power to the backplane board. Press the DIAG button to verify the 5V STBY LED illuminates.

Verify no grime or foreign debris is causing contact issues on processor connectors, and connectors on processor board and backplane board.ĥ.

Verify no bent pins on processor connector or mating connector of processor board and backplane board.

Do not reinstall processor(s), heatsinks, or memory. Reinstall processor cage with fans and processor board. If the LED does not illumuniate, suspect power supply or backplane board failure.Ĥ. Press the DIAG button, and verify 5V STBY LED (amber) illuminates.ĥV STBY LED illuminates, confirming power to the backplane board. Note: The OVTMP CPUA and OVTMP CPUB LEDs on a properly functioning Mac Pro will also momentarily flash red immediately after the Mac Pro is disconnected from AC power.ģ. If you suspect a power supply has failed,verify it in another Mac Pro if available, before replacing any modules. Generally speaking, power supplies can be affected by issues more than other modules. If they do not illuminate briefly, there is an issue with either the power supply or the backplane board. The LEDs are located under hard drive bay 1 on the backplane board.

Note: When connecting the Mac Pro to AC power, verify that the LEDs for OVTMP CPUA and OVTMP CPUB briefly flash red (less than 0.5 sec). Attach a known good power cord from a known good AC source to the Mac Pro.

Processor tray and processor board (containing processors, processor heatsinks, and memory)ĭisconnect all cables from the backplane board, except the power supply.Ģ.

Remove the following items from the Mac Pro: Take Mac Pro Down to Minimum Configurationġ.

Mac pro 5.1 cpu a and cpu b red leds manual#

Refer to other troubleshooting sections in this manual for additional direction. Note: Minimum configuration testing may not be practical for every repair. Backtrack to the previous step, remove the last installed module, and re-verify the expected behavior. If you encounter unexpected behavior during a step, you should investigate the last module you re-installed. This method may also help you discover a loose or faulty cable or connector. The goal is to identify which module(s) cause a symptom to recur when they are added. This approach helps determine which modules function together. The method gradually builds up the system from a minimum configuration and verifies expected behaviors at each step. The following procedure can help you troubleshoot a “No Power” or other startup related symptom. If computer power remains stable, the power issue is resolved. There is no other activity since there are no processors. You can tell if the computer has started up by fans and LEDs. Press power button and verify computer turns ON. Reconnect the processor board without processors. Reinstall modules until symptom reappears. Yes Suspect a module that has been removed. Verify the 5V STBY LED illuminates when you press the DIAG button on the backplane board.

Reduce computer to minimal configuration. To verify power button, go to Power Button Stuck.ĥ. Yes Front panel board or power button failure.