Use the narrow end of a plastic spudger to pull back the clip in the center of the board.

At the same time, pry the circuit board up by wedging another spudger into the top left-hand corner of the board and working it along the back, pushing the edge of the board away from the back of the clock.

The black radio antenna, which is attached to the board and comes out of the back of the clock, will need to be pushed into the clock from the outside as the board is lifted up.