Stuck in a boot loop
My computer is stuck in a boot loop. As soon as the battery is plugged in the fan turns on, computer chimes, fans stops, fan on, chime, and so on. The screen remains black throughout. I have replaced the logic board, RAM, and battery all without any improvement. Resetting the SMC and PRAM did not make any difference. If I unplug the ribbon cable from the keyboard, plugging the battery in does not start the fan or the chime, however with the cable unplugged I can’t turn on the computer at all. What do I do next?