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I swapped out the power supply and am having starting issues. I put everything back in place, went to start and nothing. I then take the glass off, take out the left speaker, double check the switch connection on the power supply and then try to boot it up without reinstalling the speaker or glass. Fires right up, fan seemed to be a little faster than usual but the glass wasn’t on so maybe not. I then reinstall the speaker and glass. Go back to start it and nothing again. What in the world is going on? Thanks in advance.
Hold off. LED 4 was not on, correct? 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. That would mean that if it is off your computer and the LCD display panel are NOT communicating. Check your logic board for any obviously damaged component and double check the display adapter connector. Post some good images of that with your question. Adding images to an existing question
What does the onboard diagnostics LED’s telling you?
Here’s a breakdown of the onboard diagnostic LED’s: LED 1 - Indicates that the trickle voltage from the power supply is detected by the main logic board. This LED will remain ON while the iMac is connected to the AC power. 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 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.
