"HDMI port has caved in. How do I fix it?"に関する回答There is a take apart video of a fellow that had the same problem with the USB connector. When his disassemble his cam and got to it, the pads were lifted from the motherboard and because of the compactness of it, there is no way to repair that. A new mobo will solve the problem.
"Powered with 12V and not work the audio"に関する回答You will need a new motherboard. And that alone may not solve all the problems. I did that but now it only turns on after the battery is removed and replaced. Go figure. This company does not provide support nor a circuit diagram or a block diagram so it is very difficult to troubleshoot.