Hi Kevin,
We have the schematics and maybe an original parts list for the '16 in the manual database.
The BillD mod was for the C-1/C-11.
The C-6/16 had more in common withe the C-19, they are a bit of a different animal and not nearly as common as the C1/11
InnovativeAudio in Surrey currently has a C-16 for sale, I assume they could service one. I have dealt with them a few times, good folks.
Which dbx unit do you have?