Apple imac 20 inch early 2008 User Manual

iMac (20-inch Early 2008)  Take Apart — Logic Board 151
On the left side of the logic board, connect the following cables, routing them as shown: 
9. 
Power button (2-pin)
•	
Ambient temp sensor (attaches to the sensor on the speaker and to the logic board)
•	
CPU fan 
•	
DC power 
•	
Note: The empty connector to the right of the CPU fan connector is for the LCD temp sensor 
cable. When the panel is replaced, connect the temp sensor cable.
With the logic board in place, press the piece of EMI tape (on...

iMac (20-inch Early 2008)  Take Apart — Logic Board 15 2
Rep11 . lace the display panel.
Replace the front bezel.
12.  
Clean and replace the glass panel13 . . Note: This step is very important. Follow the procedures 
to ensure the glass is clean and free of particles.
Replace the access doo
14.  r. 

iMac (20-inch Early 2008)  Take Apart — Video Card 15 3
Video Card
Tools
Torx T8 screwdriver• 
Preliminary Steps
Before you begin, remove the following:
A
• ccess door
Glass pane
• l
F
• ront bezel
LCD display pane
• l
Speaker, right
• 
• Logic boar d
Part Location 

iMac (20-inch Early 2008)  Take Apart — Video Card 154
Removing the Video Card 
1. Remove the three screws and disconnect the cable from the logic board.  
Tilt up the video card with attached heatsink, and disconnect it from the card connector on 2.  
the logic board (as shown with the iMac (24-inch) video card.)
922-4723
922-7971, to heatsink 

iMac (20-inch Early 2008)  Take Apart — Video Card 15 5
When handling the video card, hold it by the heat pipe brace as demonstrated on the 
3. 
previous iMac model video card. 

iMac (20-inch Early 2008)  Take Apart — Video Card 156
Replacing the Video Card
1. Make sure the CPU and GPU temp sensors on the back side of the logic board are connected.
Connect the video card to the logic board, lining up the gold fingers on the card with the 2.  
video card slot on the logic board. 

iMac (20-inch Early 2008)  Take Apart — Video Card 15 7
3. Install the three screws on the video board and connect the graphics sensor cable to the 
back of the logic board. Replacement Note: The shorter screw attaches at the far right end 
of the video card heatsink.
 
Replace the logic board.4. 
Replace the right speaker.5. 
Rep6. lace the display panel.
Replace the front bezel.
7.  
Clean and replace the glass panel8.  . Note: This step is very important. Follow the procedures 
to ensure the glass is...

iMac (20-inch Early 2008)  Take Apart — Hard Drive Fan 15 8
Hard Drive Fan
Tools
No tools are required to remove the hard drive fan.
Preliminary Steps
Before you begin, remove the following:
Access door
• 
Glass pane• l
F
• ront bezel
LCD display pane
• l
• Speaker, right
Logic boar
• d
Part Location 

iMac (20-inch Early 2008)  Take Apart — Hard Drive Fan 15 9
Removing the Hard Drive Fan 
Once the logic board has been removed, the fan can be lifted straight up and off of the three 
guide posts. 
  

iMac (20-inch Early 2008)  Take Apart — Hard Drive Fan 160
Replacing the Hard Drive Fan
Install the hard drive fan onto the guide posts.1. 
Replace the logic board.2.  
Replace the right speaker3. .
4. Make sure the hard drive temp sensor cable, the optical sensor cable, and the hard drive fan 
cable are connected at the top of the logic board before replacing the LCD panel.