Chosen Solution
No startup chime, no video, solid sleep LED, optical drive makes noise, and after staying on for a while, the part underneath the F keys gets hot. I had a question about this same problem, and it was suggested the i/o board may have been the culprit, so I replaced it. Both the LB and the i/o board were brand new - not used or refurbished. I followed the instructions here to the T, but I am just lost - I don’t have the knowledge to know what to look for or troubleshoot beyond the obvious things I’ve read about. Could it be bad wires? connectors? if my Fans were not working, could it cause the MBP to fail the POST? Thanks!
Please disconnect the hard drive, remove the battery and try starting up. Let me know your results including any lights and/or sounds. You said there was a disk in the optical drive, what is it? If it’s a system installation disk, is it the original disk that came with your computer? Did you buy this unit new? Has it ever gotten wet? Where did the new parts come from?
You may try to remove completely the top case, disconnect the hard drive, the optical drive, airport card, bluethoot cable, well everything you can disconnect from the logic board but let the dc in board connected then find the two power pad contacts on the logic board (you should see a white power icon, or PWR written somewhere). Connect the AC adapter and try to briefly bridge the two power pads with a small jeweler flat screwdriver. If the MBP powers up and you see the question mark onscreen then you know the logic board is OK and you can connect the disconnected components once at the time powering the machine between each connection until you find the culprit.
