Model A1225 / Mid 2007 and Early 2008 / 2.4, 2.8, or 3.06 GHz Core 2 Duo processor

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Repair Guide for iMac power supply replacement?

My iMac Intel 24" EMC 2211 is dead, I believe it is the power supply. I'd like to try replacing it. I understand there is no guide for my model iMac. An alternate guide was mentioned in another thread (17" iMac), but they are old posts and I wonder if the info is still good. What model iMac-PS-Replace guide should I use?

TIA!

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Helen, see if this will help you with that task:"

Power Supply, AC/DC

Tools

Torx T10 screwdriver•

Preliminary Steps

Before you begin, remove the:

Access door•

Glass panel•

Front bezel•

LCD panel•

Part Location

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Removing the AC/DC Power Supply

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

1. 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.

Note: If the computer is shut down by pulling 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.

2. Using a Torx T10 screwdriver, remove the four screws from the AC-DC power supply board. Replacement Note: Install the machine screws on the right side and the self tapping screws on the left side.

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3. Lift the power supply up to access the connectors on the underside. Pinch the black tab on the DC power supply/SATA cable connector (the bigger connector) to disconnect the cable. Carefully remove the 1-pin sensor signal cable from the underside of the power supply. (See the next photo for a close up.)

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4. This shows a close up of the 1-pin sensor signal cable connector on the underside of the power supply. Note If this sensor signal wire is disconnected or faulty the CPU fan will run at full speed

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5. Disconnect the AC power inlet cable from the power supply. The cable is tucked neatly between the right pressure wall (black piece of molded plastic along the right side of the power supply) and the top of the logic board.

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6. Lift the power supply from the rear housing.

Replacing the AC/DC Power Supply

Warning: 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.

1. Make sure the right and left pressure walls are in place. Note: There is a 240W and a 250W power supply. Make sure to order the correct power supply according to the system serial number.

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2. Connect the AC inlet cable and tuck the connector into the slot (see arrow) on the right pressure wall.

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3. Connect the DC power supply/SATA cable and the 1-pin sensor signal cable to the underside of the power supply.

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4. Replace the four T10 power supply screws. Install the machine screws (on the right side) first when installing the power supply

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5. Replace the display panel.

6. Replace the front bezel

7. Clean and replace the glass. Note: This step is very important. Follow the procedures to ensure the glass is clean and free of particles.

8. Replace the access door."

Hope this helps, good luck.

Additional Info as requested

Helen, the iMac has four built-in diagnostic LEDs on the main logic board that can help you to troubleshoot the computer. The four LEDs are located to the right of the memory slot. The photo shows a close up of the LED's.

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LED #1

Indicates that the trickle voltage from the power supply has been detected by the main • logic board. This LED will remain ON whenever the iMac is connected to a working AC power source. The LED will remain on even when the computer has been shut down or put to sleep. The LED will turn off only if the AC power source is disconnected or the power supply is faulty.

LED #2

Indicates that the main logic board has detected proper power from the power supply when • the computer is turned on. This LED will be ON when the computer is turned on and the power supply is working correctly.

LED #3

Indicates that the computer and the video card are communicating. This LED will be ON • when the computer is communicating properly with the video card. If LEDs 1 and 2 are ON and you heard the startup sound, but LED 3 is OFF, then the video card might be installed incorrectly or need replacement.

LED #4

Indicates that the computer and the LCD display panel are communicating. This LED will be • ON when the computer is turned on and video signal is being generated. If the LED is ON and there is no image on the LCD display panel, the LCD display panel or inverter might be installed incorrectly or need replacement.

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Comments:

Thank you, OT. I think this will be very helpful!

Can you tell me where in my EMC 2211 Intel iMac 24" the LEDs are that are mentioned in other threads? I don't see them near my RAM bays.

Where did you find these instructions? I'd like to find the original so I can thank the publisher.

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Helen, the publisher is Apple and I am sure that they would not like me to post their instructions, might cut back on the Apple service center jobs:-) I'll post the LED image with my original answer.

by

Thank you so much, you have been extremely helpful. When I get the part I'll follow up here with a report.

by

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The replacement of the PS went as planned and cured the malfunction. I noted that after 4 years of use, one of the transducers on the original PS was blown, evinced by a bulging case and aperture in the end of it.

Regarding the suction cups to pull off the plastic display cover: Did not want.

Instead, I took two strips of gaffer tape* (approx 12 in. long) and used those. From the middle of each strip, I pinched the duct tape to itself to form approx 2in. square "handles." Then I pressed the two strips on the left and right of the cover surface, parallel to each other and spaced well apart. The handles should be positioned at the approx. vertical center of the cover. The cover lifts off easily.

When the repair is complete, the gaffer tape is easy to peel off and leaves no residue. If you fold the gaffer tape on itself to store, you can save it for another use.

\ * MUST be gaffer tape or other reposition-able tape. NOT DUCT TAPE.

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Hello

can it be when the LED #3 is off (which should indicate the graphic card is not communicating proper with the logic board) and LED #1+2 is on, that the Power Supply is defect?

Thanks in advance for your help

Andreas

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Helen will be eternally grateful.
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