There are at least 6 screws holding in a daughterboard which holds the input selectors, volume potentiometer, and screen. Remove this, but be careful about the wires connecting to the power button. You can remove the cables if you'd like, but it is a pain to put them back together, so I wouldn't recommend it.

One screw is located in the very top left corner of the board (assuming you are looking at the rear of the machine.) The rest are in really tough to reach spots, which is why you have that Phillips Alan Key. You can use that in order to reach those screws without having to remove the cards and heatsink.

You may notice there is a brown wire wrapped around a ribbon cable. DO NOT REMOVE EITHER CABLE. Unwrap it from the ribbon cable.

Alright, now it is time to remove the daughterboard. Be very careful when removing it. You should be able to turn it, then lifting it up above the buttons. If you removed the power button, you should have no problem taking it out and resting it on a different surface. But if not, then have it on top.

If you must, then let it hang from the capacitor that is in the middle of the board.