The connection between the main board and the light engine may need to be reseated. If that doesn't work then the dmd board on the projector is probably bad. This is not uncommon for a unit this old. To reseat the connection you must remove the power input board,power supply/ballast,metal shield and then the main board screw. You can then raise up on the rear of the main board a little and pull gently towards you. It should detach from the bottom of the light engine. If you have any board cleaner you can clean and air dry the connections. After they are dry reseat the connection and make sure the board is in place. You should see some plastic rounded top guide pins poking thru the the main board towards the rear of the board. This lets you know the board is in place. Now put it all back together and hope for the best. If it still does it then your dmd board on the light engine is probably bad.