Difficulty
Moderate
Steps
6
Time Required
15 - 45 minutes
Sections
2
- Rear Panel
- 2 steps
- Power Supply
- 4 steps
Flags
0
BackiMac G5 20" Model A1076
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Introduction
What you need
Video Overview
Step 1
Rear Panel
- Lay the iMac display-side down on a flat surface.
- Loosen the three Phillips screws securing the rear panel to the iMac.
- These screws are captive in the iMac. The center screw will stop turning after about 3.5 turns and the outer screws will stop turning after about 5.5 turns. Do not try to remove these screws from your iMac.
Lay the iMac display-side down on a flat surface.
Loosen the three Phillips screws securing the rear panel to the iMac.
These screws are captive in the iMac. The center screw will stop turning after about 3.5 turns and the outer screws will stop turning after about 5.5 turns. Do not try to remove these screws from your iMac.
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Step 2
- Lift the rear panel slightly near the bottom of the iMac.
- Pull the rear panel toward yourself and remove it from the iMac.
Lift the rear panel slightly near the bottom of the iMac.
Pull the rear panel toward yourself and remove it from the iMac.
Step 3
Power Supply
- Remove the three Phillips screws securing the power supply to the chassis.
- The two leftmost screws are captive in the power supply.
- To aid in removal, it may be helpful to lift the center screw slightly away from the midplane.
Remove the three Phillips screws securing the power supply to the chassis.
The two leftmost screws are captive in the power supply.
To aid in removal, it may be helpful to lift the center screw slightly away from the midplane.
Step 4
- Rotate the center Phillips screw on the bottom of the iMac clockwise until the rear panel clamp contacts the edge of the case.
Rotate the center Phillips screw on the bottom of the iMac clockwise until the rear panel clamp contacts the edge of the case.
Step 5
- While depressing the connector lock, use a heavy duty spudger to pry the power supply connector away from its socket on the logic board.
- It will be necessary to work from alternate sides until the connector is free.
- Your power supply may have an ambient light sensor cable attached from the power supply to the logic board. If so, carefully use a spudger to push out the cable towards you using the sides of the cable alternatively to help you slide it out.
While depressing the connector lock, use a heavy duty spudger to pry the power supply connector away from its socket on the logic board.
It will be necessary to work from alternate sides until the connector is free.
Your power supply may have an ambient light sensor cable attached from the power supply to the logic board. If so, carefully use a spudger to push out the cable towards you using the sides of the cable alternatively to help you slide it out.
Step 6
- Lift the power supply slightly from its left edge, then grab each side and rotate the power supply toward yourself.
- The power supply requires a large amount of force to remove. You may need to bend the edge of the front case toward yourself for enough clearance to remove the power supply.
- There are several capacitors mounted to the logic board in close proximity to the power supply. Try not to disturb them, as they are delicate and may break off the board.
Lift the power supply slightly from its left edge, then grab each side and rotate the power supply toward yourself.
The power supply requires a large amount of force to remove. You may need to bend the edge of the front case toward yourself for enough clearance to remove the power supply.
There are several capacitors mounted to the logic board in close proximity to the power supply. Try not to disturb them, as they are delicate and may break off the board.
To reassemble your device, follow these instructions in reverse order.
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Walter Galan
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John Faughnan - Aug 10, 2011
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As usual, trickier than the video suggests. In addition to these notes, also check notes on similar power supply installs.
It is very hard to disconnect the optical sensor cable from the motherboard. There’s no hidden catch, you just have to insert your spunger/thin screwdriver blade between the fittings and gently twist. I used a surgical clamp to also pull on the cable – that did it. (The cable is being replaced, so you don’t need to worry about it).
The top right screw is hard to remove. I had to partly remove it, then lever the power supply up as in the video while continuing to loosen it.
I used thin wide screwdriver blades to disconnect the power supply connect, my spudger wasn’t rigid enough.
The supply has clearly been used before. In the context of something this old “new” means Apple refurbished. That’s fine.
Beware the optical sensor, it’s glued to the power supply. Look for it. When you insert the new supply place it first.
acohen25 - Apr 26, 2012
Reply
Thoughts about using an industrial strength air duster to rid the power supply of free radicals? Wonder it’s impact on the capacitors.
Teresa - Nov 8, 2012
Reply
This completely fixed my issue. Took all of 5 minutes and I was back up and running. Just take your time and anyone could do this. Perfect instructions and I saved $100 in repairs.