A little trick I have begun to use, buy a 15-25' 3 prong extension cord.
lay the socket end down in the rear of the cabinet, bring the wire up to the front where the on/off switch is normally located, and cut the cord in two.
Wire the switch in line with the black wire, and wire nut the white back together.
Now, the funky part.
You need another 3 prong cord, just the plug with about 2 feet of cord.
Wire the short cord with the plug into the power wires on the bottom board, and the plug will hang off the back.
plug in to use, unplug to service, and remove bottom board, without havin to mess with the cord.
the green wire at the switch, can be added to for a front door ground, lock bar, and flip switches if needed.