You would need to do some additional troubleshooting to know for certain, but it is possible that this is due to a failed DC-in board, although there's also a chance it could be due to a fault on the main logic board. If you can afford it, it might be worth ordering a replacement MagSafe board for testing. If that doesn't fix the issue, it's probably due to a fault on the main board and would require more advanced diagnostics to resolve.