I've got the exact same problem with no power switching on the Direct Connect 8 unit. I also had a similar difficulty with the screw by the RJ-11 (phone) plug just spinning. After I managed to get it off I discovered that this is just a screw to connect a ground wire to the case. You should be able to open the case without taking that crew off at all.
I received an email from neptune support; they suggest changing the fuse. The fuse is a GMA 15a 120v, 5mm x 200mm. Does anyone know where to get one of these locally (Everett/Lynnwood, WA)? I've tried RadioShack, HomeDepot and Lowes. The closest they carry is a 7a one.
Thanks,
Paul