iPhone 3GS "input controller"... like where it plugs in... is there a controller for the inputs and if it were broken what would happen?

Hello! I have posted about a similar issue before. I am a hobbyist, and a friend of mine had an old "broken" iPhone 3GS. I took interest to it, and am trying to fix it. These are the specifics: When I first got it, I tried charging it for a LONG time. At first, It would try to start iOS, then it would stop and show it was charging. After about 10 minutes, the phone did nothing at all, and responded to nothing. I put my ear up to it... something weird. It makes a faint discharge tick or zap like noise, I'd say 4 times a second. I tried for a few days to fix it, charging it and trying to restore. It kept on failing. Finally, one day, I got it to boot up. It wanted a SIM. Shoot. They had taken it out. I had just assumed they'd copied the SIM data, but I popped the tray out, and, sure enough it was gone. So I couldn't activate it. I tried to get around it with some strange emergency call bug, but I only ended up calling the police. Oops... anyway, I decided I had to install 3rd party software (I did something that would've messed up the warranty if it wasn't five years out of date). It unlocked, but 1/2 of the apps and functions would fail. I didn't know if it was hardware or software, so I tried again. Same results, only this time the phone stopped accepting charge. Everything gave me the "charging not supported with this accessory" error. It ran out of juice, and all my attempts to boot it or restore it after that failed. Now, when I plug it in nothing except the "tick" happens. At one point before there was some long or short 2-tone beeps audible too, but those are gone too. No battery logo, nothing. iTunes doesn't even detect it in DFU (recovery mode). I am suspecting that (if it is a thing) Whatever device controls what does in and out of the charging port is REALLY messed up. Or the logic board. I dunno...

Any ideas?

Thanks!!!