Is it a Video card Issue? (No Display or Black Screen)
I have replaced the power supply of an iMAC 20" Intel a1224(EMC 2210) when i finish and turn on the machine it has no display... I have noticed that the fourth diagnostic LED is not light...
601, 602, and 603 is ON, but 604 is OFF.. would it be the video card issue? just want to make sure before i replace the video card.
two weeks ago, when i received the video card i order online i immediately teardown my MAC and replace the old video card, and luckily the system is now running in very good condition.
Hook it up to an external monitor to help isolate the problem. Why did you replace the power supply and what symptoms led you to do it?
LED 1 indicates that trickle voltage from the power supply has been detected. This LED will be ON when the computer is turned off and your power supply is working correctly.
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 LCD display are communicating. This LED will be ON when the computer is turned on and video signal is being generated.
LED 4 lights only if the computer detects an over-temperature condition. This LED will be OFF when the computer is turned on and running at the correct temperature.