Battery not recharging - DC In seems to be problem?

I have a Sony Vaio PCG-V505ECP laptop. The power source and laptop are not connecting. The recharging light that usually comes one when I plug the power source into the laptop is not lighting up. I've had the power source checked and it's fine. I called Sony about the problem and they said it's probably the DC In unt which is connected to the motherboard. . . and it'll cost me $699 + shipping to get it fixed. Is there a less expensive solution? I'm a student and on a very limited budget. Could there be other explanations for the problem? Please Help