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I just bought a used imac 21.5 emc 2389 Was told power supply was replaced but its still not working. (Have reciept and old power supply so i know it was replaced) So with some help from google i checked the led diagnostic lights and light 1 and 2 light up but 3 and 4 do not. I get no chimes, no beeps, screen does not light up or do anything. This did not come with a keyboard or mouse so i will have to buy them IF i can get it to boot up. From my googling ive found that led light 3 not lighting up means that the logic board isnt recieving signal from the graphics card? Is there ANY other things to check befoe ruling its the graphic card or logic board? Would like to get this working as cheap as possible. Thanks in advanced
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. I’d pull the video card and reflow it with a hot air rework gun. You can go low dollar on it with something like this: http://www.ebay.com/itm/WEP-858D-SMD-Dig… Here’s how to get to it: iMac Intel 21.5" EMC 2389 GPU Card Replacement
