My LP 750 is dead

Hi:

When I connect my projector to the power outlet tow things happens:

1) An electrical pop up sound comes from the small speaker.
2) From the power light indicator comes an dim amber color light.

As far as I know, after I disasembled the projector, the power supply is in good condition ( I inspected the power supply inside and looks very good. Also, I found inside the power supply a green led turned on so I conclude that the power supply is in good condition). All the electronics components looks good (nothing burned). I think the problem could be the main board.

If somebody has some troubleshoot ideas it would be great. Also, I would like to know where can i find a new main board.