iMac G5 17" Model A1058 Midplane Assembly Replacement

Written By: Walter Galan

Comments: 11

iMac G5 17" Model A1058 Midplane Assembly Replacement

Difficulty

Moderate

Steps

Time Required

No estimate

Introduction

Remove your midplane assembly to gain access to your display and front bezel.

Tools

Parts

iMac G5 17" (EMC No. 1989) Lower Fan

Step 1

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.

My iMac has only ONE catch, the central one, so the two outer screws are not to be touched.

In fact, I tried so hard to unscrew them, with a good screwdriver, that my hand hurt. Knowing that some times captive things (like these screws or a faucet) can be already at the end of their travel and we only lock them further into that position, I tried both screwing and unscrewing to no avail.

paulfrancoeur -

The two outer screws each drive a locking bar that engage tabs on the rear panel.

They definitely need to be unscrewed.

Dale Stanbrough - 10/06/19

That chick MJ is sexy!!!!!

djmadcracker -

Looks like one of these screws is not like the others... a security Philips?! Never seen one of those before.

Terry Mullane -

Please Note: If your iMac has an antenna for the airport extreme and not the bluetooth card. Don't buy the bluetooth get the airport extreme instead. Also, some newer devices may not work with these units.

James Janota - 01/12/14

Just want to say thank you to ifixit! You guys are amazing and so helpful! This was so easy to do and I ordered the part I needed as well! We are up and running over here and my 7 year old son could not be any happier! Thank you!

mary nicolazzo - 16/09/16

These are the easiest way to resolve the Wireless connectivity at my home. Thanks ifixit for sharing this.

Geek Squad - 08/03/19

Step 2

Lift the rear panel slightly from the bottom edge of the iMac.
Pull the rear panel toward yourself and remove it from the iMac.

Step 3

Remove the three 8 mm brass Phillips screws securing the optical drive to the midplane.

Step 4

Lift the optical drive near the connector to separate it from the logic board.
Lift the free end of the optical drive just enough to clear the fan cover. Lifting the free end of the optical drive too far may break the plastic positioning pins off the front bezel.
Lift the free end of the optical drive slightly, then pull it away from the edge of the rear case to clear the two plastic positioning pins.
Lift the optical drive out of your iMac.
When reinstalling your optical drive it may be necessary to set the bezel attached to the open end of the drive on the plastic positioning pins molded into the front bezel of the iMac and pull the connector side of the drive toward the edge of the rear case, bending it outward slightly, to properly seat the connector.

Step 5

Slide the inverter-to-display cable connector from under the metal clip on the midplane.

Step 6

Disconnect the inverter-to-display cable connector by pulling it straight away from its socket.

Step 7

Remove the single Phillips screw securing the inverter to the logic board.
Lift the inverter straight up off the pins on the logic board.
Be sure to lift the inverter straight up off the logic board, as the connector pins are very long and easily bent. If the pins bend during removal, use the connector on the inverter as a guide to bend them straight.

Step 8

De-route the inverter cable connector from the channel in the logic board.

Step 9

Disconnect the inverter cable from the logic board by pulling it straight up from its socket.
Replacement note: it may be helpful to carefully reattach this connector before seating the midplane assembly, making sure the connector safely passes through the hole in the midplane assembly.

Step 10

Rotate the center Phillips screw on the bottom of the iMac clockwise until the rear panel clamp contacts the edge of the case.
On our specific machine, the threaded portion of the clamp broke off the clamp body causing the center screw to turn without moving the bracket. If your machine is broken like ours, skip to the next step.

Step 11

While depressing the connector lock, insert the flat end of a heavy duty spudger into the gap between the power supply connector and its socket.
Twist the heavy duty spudger to slightly separate the connector from its socket.
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 12

Pull the power supply connector straight away from its socket on the logic board.
This step is very simple if you remove the power supply first.

Step 13

Remove the three Phillips screws securing the power supply to the chassis.
All three 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 14

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.
Grab the power supply from each side and rotate its top edge toward yourself until it clears the logic board.
Lift the power supply out of the midplane.
The power supply requires a large amount of force to remove. You may need to slightly bend the edge of the front case toward yourself for enough clearance to remove the power supply.

Bend the case at the rear panel clamp enough to clear the panel clamp while lifting out the power supply using the two captive screws as handles.

timothychilders -

Rolling the power supply towards you while lifting using the captive screws helps get it past the captive back cover screw from step 4.

themackey -

My replacement power supply did not come with an Ambient Light Sensor. I thought I had gotten the wrong one, but in fact the ALS comes easily off the old power supply (using a small flathead screwdriver to pry it off) and attaches to the new one.

Calion -

Step 15

Remove the two Phillips screws securing the fan cover to the midplane.
The shouldered screw belongs in the lower left corner of the fan cover.
Lift the fan cover up off midplane.

Step 16

Remove the two Phillips screws securing the display data cable to the logic board.
Using its black pull tab, pull the display data cable connector straight up off its socket on the logic board.

Step 17

Remove the six Phillips screws securing the midplane to the front bezel.
The three shorter screws fasten along the top edge of the iMac.
The three screws along the top of the iMac often fall down into the front bezel when removed. We recommend using a magnetic screwdriver or placing a strip of duct tape over the tip of your screwdriver to help keep the screws from falling into the front bezel.

Step 18

Using its attached pull tab, lift the free edge of the midplane assembly slightly out of the front bezel.
Don't completely remove the midplane assembly just yet.

Step 19

Push the inverter-to-display cable connector through the hole in the midplane.
Lift the now-free midplane assembly out of the front bezel.

Conclusion

To reassemble your device, follow these instructions in reverse order.

Author

Walter Galan

694047 Reputation

One comment

The picture on the far right for step 11 shows disconectting the ambient light sensor cable, not the power supply connector.

themackey -