Coax-Optical Instructions Interior Overview Circuit Board Underside Jacks   Power Supply Wiring Case Underside Case Switch & Power Jack   As you can see, the hole for the TOSlink transmitter is rather poorly done - there's only so much accuracy one can squeeze from a soldering iron. :) If you're looking for a cleaner cut, you can also try a nibbling tool. In the end, I decided not to redo the cut because plugging in the TOSlink cable conveniently covers the cavity edges and then some.