Model A1224 / Mid 2007 and Early 2008 / 2, 2.4, or 2.66 GHz Core 2 Duo processor

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Video issues with diagnostic LEDs

About two weeks ago my Intel iMac (EMC2210) failed to boot. Upon pressing the power button I could hear the fans spin up, but the screen remained black and there was no startup chime.

So, I began looking for what might have happened. I hooked up an external monitor and got nothing. I searched here and ran across a description of the diagnostic LEDs. So, I checked the diagnostic LEDs.

#1 lights up when I plug in the power cord.

#2 lights up when I press the power button and stays on.

#3 lights up for a brief time when the power button is pressed and then goes out.

From the answers that I found on the diagnostic LEDs I figured that the video card had went bad. But this is where I am stumped. I ordered a brand new video card for the iMac and just finished installing it. Unfortunately, there is no change in the behavior of the computer. LEDs 1 and 2 still light and LED 3 still blinks and then goes out.

I am stumped. Could it be a bad power supply despite the #2 LED coming on? Could it be a bad mainboard? Is there any way to know if it is a bad mainboard? I don't want to sink any more money into the machine if it is toast. Any help or suggestions on what to check would be greatly appreciated.

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Is it an iMac early 2008?

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Yes, it is an early 2008 - MB324LL/A - iMac8,1 - A1224 - 2210 model. They really have a lot of ways to denote a machine.

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Chosen Solution

LED Startup Sequence

LED #1 = Power available.

If no LED is visible:

• Verify AC source

• Verify known-good AC cable is connected

• Verify cable connection between AC inlet and power supply

• Verify cable connection between power supply and logic board

• Verify power supply

LED #1 + LED #2 = Power available, and system is powered on.

If second LED is not visible when power button is pressed:

• Verify power button connection to logic board

• Verify power button functionality

• Verify cable connection between power supply and logic board

• Verify power supply

• Verify logic board

LED #1 + LED #2 + LED #3 = Power available, system is powered on, and video card found.

If third LED is not visible after power on:

• Verify that MXM video card is seated properly

• Verify logic board

LED #1 + LED #2 + LED #3 + LED #4 = Power available, system is powered on, video card found, and internal LCD found.

If fourth LED is not visible after power on:

• Verify cable connections between LCD panel and logic board

• Inspect LCD display cables for cable damage

• Verify external video functionality, and according to result check the following items:

-If external display works then verify/replace LED backlight board

-If external display works then verify/replace LCD panel

-If external display does not work verify/replace logic board

Was your video card supplier a reputable one?

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This is what I had found earlier. Therefore, since I have tried two different video cards I am going to guess that it is the logic board. Therefore, how do I verify the logic board?

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Apple's idea of verifying is Replace it and see if the new one works.

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That is what I was afraid of. Thank you for all of your help.

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drumheller74 will be eternally grateful.
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