Apple imac usb 2 0 User Manual

							
72 - iMac (USB 2.0)  Take Apart
 Chassis (Faraday Cage)
Chassis (Faraday Cage)
Tools
This procedure requires the following tools:
• Torx-10 screwdriver
• Torx-8 screwdriver for the logo screw
Part Location
Preliminary Steps
Before you begin, do the following:
• Position the computer in the service stand.
• Remove the user access plate.
• Remove the bottom housing.
• Remove the drive carrier assembly. 
						

							
 iMac (USB 2.0)  Take Apart - 73
 Chassis (Faraday Cage) • Remove the power supply.
• Remove the fan.
• Remove the plastic cable retainer (under the fan).
• Remove the neck spoke retainer cap.
Procedure
1. Pull the neck cables/white spokes out of their slots and into a bundle. Bundle the neck 
cables to one side. Supporting the base, remove the two black screws that connect 
the neck to the Faraday base. 
						

							
 
74 -  
 iMac (USB 2.0)  Take Apart  Chassis (Faraday Cage)
2. Carefully feed the neck cables through the hole in the Faraday cage. 
 
Important:
 
  The 
Faraday cage is very heavy and has sharp edges; handle with care. 
						

							
 
 iMac (USB 2.0)  Take Apart -   
75  
 Chassis (Faraday Cage) 3. Pull the outer shell (with Faraday attached) away from the neck.
Note:  There is no 
need to remove the outer shell from the Faraday unless you are replacing the antenna 
or the outer shell. If you are removing the shell from the Faraday cage, go on to the 
next step.
4.  Perform the next step only if you are replacing the Faraday, the antenna, or the outer  shell. 
5. Remove one screw in the base of the Faraday cage to separate the shell from the  Faraday cage.  Note: The Faraday cage on the 20-inch iMac (USB 2.0), 922-6204, is 
heavier and different from the Faraday cage used on the 15-inch and the 17-inch iMac 
(USB 2.0) computers.  
						

							
76 - iMac (USB 2.0)  Take Apart
 Chassis (Faraday Cage)
Replacement Notes: 
Faraday cage: 
Look at the exploded view diagram during reassembly. First, attach the 
Faraday top cover to the top (OUTSIDE) of the Faraday cage  as shown below; the 
Faraday top cover is  keyed. Next, thread the neck cables through the hole in the Faraday 
cage and install the Faraday cage into the top plastic housing. Replace the screw that 
holds the plastic housing to the chassis. Attach the black neck cap screws to connect the 
neck to the chassis. Route the neck cables correctly in the base and replace the fan 
bracket retainer and three remaining neck cap screws.
Warning:  Whenever the bottom housing is opened for service, you must do two things:
1.You must clean the original thermal film from all thermal interface ma\
ting surfaces, 
and reapply thermal paste to the mating surfaces on the thermal pipe.
2. You must tighten the four torx screws on the bottom housing to a mini\
mum of 17 
in.-lbs. Use a torque driver (service tool 076-0899) to ensure that th\
e thermal pipe is 
firmly mated with the top base. If you do not have a torque driver, you \
must make 
sure the screws are tightened by hand FIRMLY, BUT NOT FORCIBLY. 
Failure to follow these steps could cause the computer to overheat and 
damage internal components.
Refer to the topic “Thermal Paste Application” for detailed inform\
ation. 
						

							
 iMac (USB 2.0)  Take Apart - 77
 Antenna, Wireless
Antenna, Wireless 
Tools
This procedure requires the following tools:
• Torx-8 screwdriver
Part Location
Preliminary Steps
Before you begin, do the following:
• Position the computer in the service stand.
• Remove the user access plate.
• Remove the bottom housing.
• Remove the drive carrier assembly.
• Remove the power supply.
• Remove the power supply insulators.
• Remove the optical drive door.
• Remove the internal speaker.
• Remove the fan. 
						

							
78 - iMac (USB 2.0)  Take Apart
 Antenna, Wireless
• Remove the fan bracket under the fan.
• Remove the neck spoke retainer cap.
• Remove the blind mate connector screws.
• Remove the Faraday cage. 
						

							
 iMac (USB 2.0)  Take Apart - 79
 Antenna, Wireless
Procedure
1. Remove the mounting screw and unclip the board from the Faraday cage. Remove 
any tape, and carefully separate the antenna board cable from the Faraday cage.
2. Remove the second mounting screw to unclip the antenna from the Faraday cage. 
						

							
80 - iMac (USB 2.0)  Take Apart
 Antenna, Wireless
Replacing  the AirPort Antenna
Procedure
1. Attach the replacement antenna to the outside of the Faraday cage. Feed the antenna 
wires through the Faraday cage and position the wires against the Faraday cage (as 
shown).  Note: Make certain the wires lay flat against the Faraday cage.
2. Feed the antenna wires through the hole in the Faraday cage and position the wires  against the Faraday cage (as shown). Make sure that the wires lay flat against the 
inside of the Faraday cage. 
						

							
 iMac (USB 2.0)  Take Apart - 81
 Antenna, Wireless 3. Place the copper tape over the wires making sure the wires lay flat. Press the copper 
tape securely against the Faraday cage. 
4. Reassemble the computer and return the system to the customer.
Warning:  Whenever the bottom housing is opened for service, you must do two things:
1.You must clean the original thermal film from all thermal interface ma\
ting surfaces, 
and reapply thermal paste to the mating surfaces on the thermal pipe.
2. You must tighten the four torx screws on the bottom housing to a mini\
mum of 17 
in.-lbs. Use a torque driver (service tool 076-0899) to ensure that th\
e thermal pipe is 
firmly mated with the top base. If you do not have a torque driver, you \
must make 
sure the screws are tightened by hand FIRMLY, BUT NOT FORCIBLY. 
Failure to follow these steps could cause the computer to overheat and 
damage internal components.
Refer to the topic “Thermal Paste Application” for detailed inform\
ation.