Chosen Solution
Hi there, The graphics card in our iMac Mid 2011 model packed in. Upon replacing the card, the Mac now has a black screen and does not chime. On the logic board, only one LED comes on. If the computer is turned on, this led remains on then after roughly 10 seconds, the fans increase to their maximum speed. I’ve tried testing the pin voltages. Pin 3 has zero volts when I assume it should be 5V to power the Hard Drive? Could anyone advise me on what steps to take? I’m stumped at this point.
You really need the schematics to trace out the power lines on the power supply and logic board.
