Use your finger(s) to start lifting the motherboard from the control box casing. While doing so, use your other hand to push the DVI connector into the control box casing.

When the DVI connector has cleared the casing, lift the motherboard.

Be careful! There should be two sets of wires still connected to the control box - do not tug on them. Simply flip the motherboard over to access these wires.

When reassembling the device, ensure that all of the wires are clear of the buttons.