Apple power mac g5 early 2005 User Manual

							
116 Power Mac G5 Take Apart

Logic Board: Power Mac G5 
Tools
The only tools required for this procedure are a long-handled Phillips screwdriver, a short-
handled Phillips screwdriver, and a hex wrench.
Preliminary Steps
Before you begin, open the computer, lay it on its side with the access side facing up, and remove 
the following:
Front inlet fan assembly
Heatsink cover(s)
Processor(s)
All AGP and PCI cards
Rear exhaust fan assembly
PCI card guide
Speaker/fan assembly
Front panel board cable
Memory DIMM if it is in slot next to the power supply cable
Power supply
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Part Location 
						

							
118 Power Mac G5 Take Apart

Procedure
Disconnect the six cables from the top of the logic board.
Using a hex wrench, remove the four standoffs for the upper processor. Using a Phillips 
screwdriver, remove the remaining processor standoff (marked by a square in the illustration 
below). Repeat the procedure for a second processor, if installed.
Remove the five screws that secure the logic board.
Carefully tilt the logic board up and maneuver it out of the enclosure, making sure the ports 
clear the enclosure openings. 
Note: Perform the following procedures only if you are replacing the logic board with a new 
logic board.
Transfer the following from the original logic board to the replacement board (see individual 
procedures in this chapter for detailed steps): 
•  Memory DIMMs
 
•  AirPort Extreme Card (if installed)
 
•  Bluetooth card (if installed)
 
•  Modem (if installed)
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Disconnect the thermistor from the logic board. 
Warning: You must disconnect the thermistor from the logic board or you will damage the 
logic board when you remove the PCI divider in step 9.
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Disconnect the front inlet fan cable from the logic board.
Remove the three PCI divider mounting screws and remove the divider (with PCI card guide 
and thermistor attached) from the logic board. 
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Replacement Note for Power Mac G5 (June 2004 Dual 1.8 GHz): If the original logic board 
routed the modem filter board and antenna board cables on top of the board, and you are 
installing a replacement logic board that routes the cables under the board, you must add 
a cable guide (bundled with the replacement logic board) to the side of the PCI divider. You 
will use this guide to hold the cables for modem, AirPort, and Bluetooth cards if these cards 
are not installed in the computer.
Position the PCI divider on the replacement logic board and install the three mounting 
screws.
Connect the thermistor and front inlet fan cable to the logic board.
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Route the modem filter board cable and antenna board cables along the PCI divider. 
Note: Be careful that the cables route under the black connector for the front inlet fan. In 
addition, make sure that the cables are in place behind all cable guides and that the modem 
filter cable routes out through the correct opening in the PCI divider.
Connect the modem filter cable to the modem and install the modem on the logic board.
Install the AirPort Extreme Card and Bluetooth card on the logic board and connect their 
cables to the cards.
Install the memory DIMMs on the logic board.
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Transfer the port EMI shield from the original logic board to the replacement logic board, 
making sure the shield is fully seated on the ports.
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Replacement Procedure
Temporarily tape the top six cables to the media shelf so that they are out of the way. 
Note: You may find a long strip of packing tape useful in securing the cables.
Angle the logic board into the enclosure so that the port edge goes in first.
Position the logic board on the three guide pins, aligning the ports with the openings in the 
enclosure. 
Slide the board toward the rear of the computer so that the logic board locks onto the guide 
pins and the ports are fully seated in the back panel openings. 
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Note: When installing the logic board into the computer, make sure the antenna board 
shield is not bent back away from the case. The shield should touch the case when the logic 
board is fully installed.
Replace the logic board screws and standoffs.
Connect the six cables at the top of the logic board to the board.
Replace the power supply and reconnect all power supply cables to the logic board.
Replace the front panel board cable.
Replace the speaker/fan assembly and reconnect its cables to the logic board.
Replace the PCI card guide.
Replace the rear exhaust fan assembly and reconnect its cable to the logic board.
Replace all AGP and PCI cards.
Replace the processor(s).
Replace the heatsink cover(s).
Replace the front inlet fan assembly.
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