The screws are located at 12 o'clock, 3 o'clock, 6 o'clock and 9 o'clock, just inside the outer ring.

You will need to unscrew these if possible, on my unit they were glued in and I was unable to unscrew them. Instead I used a drill with a 1/8" bit to drill them out.

If you drill them out be careful as they are surrounded by a PCB, though I drilled into the board a bit and it still functions. Once you remove the screws use the spudger to pry the shiny black plastic face off the base.

You will see the seam where the shiny and matte plastic meet on the unit. There are 4 plastic clips holding it down, once they are unclipped you can remove the shiny black faceplate exposing the charging coil and main PCB.