Judging by what you report it would suggest that the power socket changeover contacts that switch the camcorders input power from battery to mains (adaptor) when you insert the plug into the camcorders power socket have not returned to their correct closed position. Rectifying this generally involves taking the rear section of the casing off, however you could try something that has been known to succeed in a few cases, that being to rapidly pull the power plug out and in the camcorders socket about five or six times as sometimes that will encourage the contacts to take up their correct position again, it can also sometimes be of benefit by giving the inside of the socket a small squirt of electrical cleaner and immediately turning the camcorder around 360 degrees to allow the cleaner to run onto the contacts. (immediate further plug out / in procedure also assisting) Apart from whats been mentioned, also check to make sure that the connections inside the battery recess that the battery presses on are OK as far as each of them having a similar appearance and one hasnt become dislodged.