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how it’s possible to be off the diagnostic led 1 on my imac and still open??? the 3 others led are on…its starts but has bad graphics after login screen.please somebody explain me…
Because your system has two graphics systems one built into the CPU and the other is the dedicated GPU. If you boot up within Target Disk Mode you should see the FireWire Icon on your screen. If you boot up under Safe mode you should be able to see your display using Intel’s Iris Pro graphics services within the CPU. Update (08/01/2019) Whats confusing here is your question is a somewhat backwards. I’m going to assume the real question is your #1 LED is on but the others are all off. As per this 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. I would replace the power supply iMac Intel 27" EMC 2309, 2374, 2390 or 2429 Power Supply following this guide iMac Intel 27" EMC 2309 and 2374 Power Supply Replacement
Hey Dan! I have replaced the logic board and thw power supply, and i m trying to set up the ssd with the original DVD mac os x 10.0.2 but i get an error … and the process stop. any suggestions?
