I had to replace my laptop's damaged DC jack and am having trouble getting it to power on following the repair.
The part I replaced was a small board, separate from the motherboard, that housed the DC jack as well as a handful of other connections. It was an easy swap to make, but required complete disassembly of the laptop to do.
Once I got the laptop back together it booted automatically when plugged in. Once it is powered off, however, it will not turn back on with the power button. Removing the CMOS battery allows the computer to be turned on again when plugged in.
When it is on, the power button is functional. Pressing it turns off the computer, but won't turn it back on.