We would need to know what the LEDs are monitoring to make any comments on the board.

Looking through CNCzone, one person mentions that there is no flyback protection diode for the 12V line, which can kill the regulator, and also that there is no heat sink on the 12V regulator. This obviously changes from board to board but if your 12V reg has blown then that might explain why some things light up but only dimly.

Adrian.