iMac Intel 27". EMC 2309 (Late 2009, Core 2 Duo 3.06 or 3.33 GHz), EMC 2374 (Late 2009, Core i5 2.66 GHz or Core i7 2.8 GHz)

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No booting, S.O.S beeping, black screen

After pushing the start button, my mac gives 9 beeping (S.O.S. signal) the screen is black. No booting, fans are working but the keyboard is frozen.

The diagnostic LEDs:

RAM and display are not connected.

LED1 is lighting

LED2 is lighting after pushing start button.

LED3 and LED4 are not lighting.

What can be the problem? Logical board or graphic card?

thanks for your help

Answered! View the answer I have this problem too

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Did anybody this same problem?

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3 Answers

Chosen Solution

Krisz, looking at the diagnostics code for the LED's:

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 and that logic board voltage regulators are functioning properly. 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 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 display, then the LCD panel, the LED backlight board, or the cables between might be installed incorrectly or need replacement.

I'd start off with the video card. Hope this helps, good luck.

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oldturkey03, many thanks for your help. i know the code of led's. but i am wondering that somebody has already had this beeping.

when in this openedn condition (without display and RAM's) connetcting AC power source and turning on my computer, there is only one beep continueily and LED1 and LED2 lighting. When i tried this without graphic card there was the same.

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That does sound right. Once you remove the graphics card (in theory) LED 3 should be off since there is no communication to it.

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yes, i think the same. but what would mean the s-o-s signal?

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Krisz will be eternally grateful.
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