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

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No display on my iMac 20" A1224

No display on my iMac and noting rear light

i have connected an external monitor and function;

i have see the diagnostic led:

led 1 is ever on;

led 2 is on when i press the power button;

led 3 blink one second and light on

led 4 is ever off.

I have disassamble the panel and i have test the supply of the panel, but the 5v

of the pin 28- gnd of the panel there isn't.

I suppose the graphics card hasn't problems, otherwise the external monitor will not work

You have the schematics of the logic board

mt mail is silv-17@libero.it

dear Silvano

Answered! View the answer I have this problem too

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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

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Seriously? I have same problem with mine, only sometimes can I get the boot up sound... no video on internal display and no video on external display. Is there nothing on the logic board that can be replaced? What would have caused this?

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silvano will be eternally grateful.
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