Apple imac 20 inch mid 2009 User Manual

							iMac (20-inch, Early/Mid 2009) Take Apart — General Information 91 2010-11-24
Required Special Tools for Glass Panel
Special tools are required to remove, handle and clean glass panel.
• 922-8252 – Suction cups, Pkg of 2
•  922-8253 – Gloves, lint-free, anti-static, Pkg of 2
•  922-8258 – ESD bags, 24”x20”, Pkg of 5.  To prevent buildup of static charges which may 
attract dust particles, store LCD panel in an ESD bag when it is removed from unit.
•  922-8259 – Microfoam bag to store glass panel, Pkg of 5
•  922-8261 – Sticky silicone roller (6-inch) to clean glass panel
•  922-8262 – Sticky sheet pads to clean silicone roller
•  922-8263 – Polishing cloths, anti-static, optical-grade micro-terry, Pkg of 5
Cleaning Tools Starter Kit
The following tools are offered in the cleaning starter kit (076-1277):
• Suction cups, 1 pair
•  Gloves, lint-free, anti-static, 2 pairs
•  Sticky silicone roller (6-inch) to clean glass panel
•  Sticky sheets to clean the silicone roller, 2 pads
•  Polishing cloths, clean, anti-static, optical-grade micro-fiber “terry” style, 5 cloths
•  Microfoam bag to store glass panel, 5 bags
•  ESD bag for LCD panel storage, 5 bags  
						

							iMac (20-inch, Early/Mid 2009) Take Apart — General Information 92 2010-11-24
Cleaning & Handling the Glass Panel
Follow cleaning procedures in this manual to ensure glass panel is free of dust and other 
particles before returning the computer to customer.
• The glass panel is not tempered and will break into sharp pieces of mishandled.   
A scratched or broken glass panel is not covered under warranty.
•  Removing glass panel requires special tools such as lint-free gloves, rubber suction cups, 
and microfoam storage bags.
•  To prevent contamination, wear lint-free gloves and handle glass only by edges.
Do’s and Don’ts
DO
• Handle glass panel using lint-free gloves.
•  Use only a sticky silicone roller to clean the inside surface of glass and LCD panel.
•  Use iKlear ONLY on the outside surface of glass panel.
•  Place glass panel into a clean protective microfoam bag when removed from unit.
•  Store glass panel in a safe area where it will not be broken or damaged.
•  Store LCD panel in an anti-static bag to prevent buildup of static charges which may attract 
dust particles to display’s surface.
•  Store silicone roller and sticky paper within a temperature range of 39-104 F (5-40 C).
•  If silicone roller is no longer tacky, wash it in warm soapy water or wipe with isopropyl 
alcohol.  If tackiness does not return, replace silicone roller.
DON’T
•  Touch inside of glass with bare hands or dirty gloves.  Fingerprints are difficult to remove.
•  Place glass panel onto a work surface where it may collect dust and other contaminants 
unless it has first been placed into a protective microfoam bag.
Handling a Broken Glass Panel
The glass panel is not tempered and will break into sharp pieces if mishandled. If the glass is 
broken it must be carefully removed from the unit to prevent irreparable damage to the front 
surface of the LCD. If the front surface of the LCD is scratched by broken glass, the LCD may 
need to be replaced.   
						

							iMac (20-inch, Early/Mid 2009) Take Apart — General Information 93 2010-11-24
How to Remove a Broken Glass Panel
A shattered panel can be removed using safety glasses, packing tape, and leather gloves. 
1.  Put on the safety glasses and leather gloves. 
2.  Lay the computer on a smooth, clean work surface.
3.   Peel protective covering off the front of the glass. Remove and discard any large pieces of 
broken glass.  
						

							iMac (20-inch, Early/Mid 2009) Take Apart — General Information 94 2010-11-24
4. Apply a strip of packing tape horizontally across the top and bottom of the glass panel. 
Next, apply the tape diagonally, across the broken glass panel, forming an “X.”
5.   Continue applying tape horizontally, thoroughly covering the broken glass. Most of the glass 
will still be attached to the steel ring that runs around the perimeter of the glass panel.  
						

							iMac (20-inch, Early/Mid 2009) Take Apart — General Information 95 2010-11-24
6. Use a black stick to pry the glass panel off the magnets on the rear housing.
7.  Lift the entire glass panel off the rear housing.  
						

							iMac (20-inch, Early/Mid 2009) Take Apart — General Information 96 2010-11-24
8. Place the broken glass inside a large box, label the box, and dispose of it properly. 
9.   Using a whisk broom, clean the work surface of tiny glass particles.
10.  Stand the iMac up and use a lint free cloth to carefully brush any of the particles off the 
iMac onto the table. Clean the work surface again.
11.  When the repair is finished the cloth should be disposed of immediately.
12.  Use a broom and dustpan to sweep up as much of the broken glass as possible. Glass 
fragments may have traveled several feet from the location of the glass panel, so be sure to 
thoroughly clean the entire area. Use a vacuum to remove the smaller fragments not picked 
up by the broom.
Note: A broken glass panel may leave one or more scratches on the LCD display depending on 
the severity of the glass breakage. As long as the LCD itself has not been fractured the LCD does 
not require replacement, but be sure to let the customer know that the scratches are there and 
were caused by the broken glass panel.  
						

							iMac (20-inch, Early/Mid 2009) Take Apart — General Information 97 2010-11-24
Safety
Warning: HIGH VOLTAGE: The AC/DC power supply PCB remains powered up whenever the 
system is plugged in, whether or not the system has been turned on. Use extreme caution 
when troubleshooting the system with the front bezel removed.  • Don’t work alone. In the event of an electrical shock it is important to have 
another individual present who can provide assistance. 
•  Keep one hand in your pocket when working on any iMac system that is plugged 
in. This will help ensure that your body does not provide a path to ground in the 
event that you accidentally make contact with the line voltage. 
•  Don’t wear jewelry, watches, necklaces, or other metallic articles that could 
present a risk if they accidentally make contact with the power supply circuitry. 
Use extreme caution when working around the power supply. The power supply contains a 
high voltage capacitor that may remain charged for several minutes even when the computer is 
unplugged. Never touch the leads on the top side of the power supply, especially the capacitor 
leads located near the warning sign.
Important: If the computer is shut down by removing the power cord, allow the power supply 
a good 2-3 minutes to discharge the capacitors before handling it.  However, if you select “Shut 
Down” via the Apple menu, the computer will discharge the power supply capacitor almost 
immediately.  
						

							iMac (20-inch, Early/Mid 2009) Take Apart — General Information 98 2010-11-24
Logic Board Handling
IMPORTANT: Always use two hands to support the logic board and heatsink.  Handling the 
board incorrectly could flex the board and damage the chips and circuitry.
Never handle the board by the heatsink.  
						

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Reassembly Steps
When there are no replacement steps listed, replace parts in the exact reverse order of the 
Removal procedure. 
Images in This Guide
Small differences in appearance between the images pictured and the actual computer you are 
servicing may exist, however the steps and sequence are the same unless otherwise noted.
Screw Sizes
All screw sizes shown are approximate and represent the total length of the screw.  
						

							iMac (20-inch, Early/Mid 2009) Take Apart — Access Door 100 2010-11-24
First Steps
• Shut down computer.
•  Unplug all cables and 
the power cord.
•  Put on ESD strap.
•  Place computer face 
down on a clean, flat 
surface so the bottom 
is facing you.
Tools
• ESD wrist strap
•  Clean, lint-free cloth
•  Phillips #2 screwdriver
Removal
1 
Loosen captive 
Phillips #2 screw.
2 Remove access door 
(922-8186).
Access Door