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Hey, I’ve changed the graphic card on my iMac (late 2009) and now i can’t start my mac anymore. I’ve already changed the graphic card once and the imac worked perfectly after that. But now, first when i started, I heard the interior start, but no chime, no start/boot. Then i removed it and put it back in and now there is also no noise anymore and no booting. The card is the right model and I dont think I’ve connected the cables the wrong way. I’ve also checked the power cable, unplugged, re-plugged after 10 seconds etc. Unfortunately I can’t see the diagnostic lights, because of the black tape covering it and I can’t remove it correctly without maybe damaging the motherboard. Any ideas what the problem could be? Thanks in advance, Thomas Update (22.11.2018) Ok, thanks, I’ve removed the tape (how difficult can one make it?) So LED 1 is on, when i hit the power button, the light goes off and no light is on. Does this indicate the power supply is damaged?
If you are talking about the small piece of black electrical tape at the very edge of the bottom of the logic board, just remove it to reveal the diagnostic LEDS.
What does the onboard diagnostic LED’s telling you? Here’s a breakdown of the onboard diagnostic LED’s: LED 1 - Indicates 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 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 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 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. Update (11/22/2018) It does sound like you’ll need to check your power supply connections is the connecter fully seated? Did you have a hard time disconnecting it or putting it back?
