I would suggest starting with the easiest thing - try cleaning the micro-USB port in the phone. Some conductive material may have gotten caught in it, causing a short circuit. Use a wooden toothpick, a compressed air, and a magnifying glass with a light for a visual check.
If this doesn't help, try a different charging cable, as it might also be a problem with the connector on the cable's end.
If the problem persists, the phone has to be taken apart to diagnose this.
Edit: sorry, didn't notice you have already tried another cable...
Optimus G F180S, Sling v2.2.2
Xperia X10 Mini, rooted stock 2.1
MeMO Pad HD 7 ME173X, rooted US stock 4.2.2
To whom it may concern: STOP nagging about pressing the freakin' Thanks button!!! It is rude, stupid, and annoying as hell. I am not an idiot who needs a huge in-my-face reminder to press it, and I will press it when I feel thankful, not because you asked for it!