The video and control inputs, buttons, and LCD display are all part of one assembly. To remove it:

This brown ribbon cable handles all the data going to and coming from this board. Disconnect it gently from the rear panel - a plastic spudger tool can help with this.

There is a Molex-style power connector. Depress the lock tab, and pull it out.

Now, lift the interface board up. It might bind on the right side where it fits into a plastic tab on the projector bottom.