Power Management Unit (PMU) is basically a PC that exists and works in PowerMac G5. It works many low-level tasks, containing running PC's real-time clock and handling the fan. Occasionally, a PMU can become unsteady, resulting in variable system performance, containing power and sleep problems, display anomalies, and abnormal fan noise. Apple Computer advises reserving PMU resets as a last resort, after PRAM and NVRAM resets.

Instructions

Reset PowerMac G5 PMU

Shut down PC by choosing "Shut Down" from Apple menu. If system is insensitive, press power button until PC shuts down.

Step 2

Detach power cord and wait two minutes.

Step 3

Connect power cord and continue regular use.

Reset PowerMac G5 PMU (Early 2005)

Step 1

Shut down PC by choosing "Shut Down" from Apple menu. If system is insensitive, press power button until PC shuts down.

Step 2

Detach all cables and peripheral cords.

Step 3

Ground manually and find PMU button, under collection of 4 RAM slots. The button itself is a circle on top of a silver square.

Step 4

Firmly push PMU button one time.

Step 5

Again put all cords and cabling take out in Step 2.

Step 6

Start PC and start again regular use.

Reset PowerMac G5 SMU (Late 2005)

Step 1

Shut down PC by choosing "Shut Down" from Apple menu. If system is insensitive, press power button until PC shuts down.

Step 2

Open and take out both external metal door and the internal air deflector.

Step 3

Take out fan assembly. This is placed at the left of the processor.

Step 4

Find and press SMU reset button below and to right of 4 RAM slots. Press button only one time.

Step 5

Again install fan assembly, air deflector, and outer door. Restart PC and keep on utilize as regular.