How to Replace a G4 Power Supply

The Power Mac G4 computer comes with a 400-watt power supply that has been known to make a large amount of noise while the machine is running. Apple has provided free replacement power supplies that have slightly less wattage and run much more quietly. If you don't have an Apple authorized service center in your area you can replace the power supply on your own at home.

Things You'll Need

• Screwdriver
• Allen wrench
• Replacement power supply

Instructions

1. 

   Turn off your Power Mac G4 and remove all cables from the back of the case.

2. Touch your hand to the metal PCI slot covers on the back of the case to discharge any built up static electricity in your body.

3. 

   Pull up on the plastic latch on the left side of the case to unlock the side panel and then pull the latch down to pull the entire side panel off of the case

4. Locate the hard drive on the bottom edge of the top side of the case. Pull out the cables connected to the hard drive. Push down on the metal carrier over the hard drive and slide the entire unit slightly out. Use a screwdriver to remove the screws holding the carrier to the case. Remove the hard drive and carrier from the case and set it aside.

5. Find the optical drive at the top end of the case that is surrounded by a metal encasement. Grab the two finger holes on the back side of the encasement and slide the panel off. Take out the screws on the top and bottom of the encasement and pull the entire unit off. Disconnect the cables running from the optical drive to the logic board. Set the optical drive aside so that the power supply fan is visible.

6. 

   Pull up on the latch that holds the fan into place. Pull the fan out of the case and then remove the cables running from the power supply to the logic board. Turn the entire case around so that you can see the back end. Insert an Allen wrench into the port just behind where the power supply is located and remove the screw inside.

7. Turn the computer around again and pull the power supply out of the case. Set the new power supply into the case and then re-connect the screw on the back side. Re-assemble the computer by placing back in the optical drive, the hard drive, and their associated screws. Lift the side panel back up and close the case.

8. Connect the cables back into the case and power the Mac G4 on to ensure that the power supply is working properly.

Tips & Warnings

• Keep several different containers nearby as you work so that you can keep all of the different sized screws together in a safe location.

• If you damage any of the internal components on your G4 computer while replacing the power supply you will void the warranty provided through Apple.

Resources

• Purchase Replacement Power Supply at Newegg
• Mac G4 Support Website