I'm in the process of repairing two BOSE 2683-1 Acoustimass Subwoofers (two ports, one 8-inch driver, three amplifiers) and would be willing to share an abundance of info about it in return for a decent quality copy of the schematic diagram.
The current version I have is an almost unusable 470 KB JPEG created from a photograph or a scan of a rather tattered, taped foldout that I got from the eservice info.com website.
If you have a clean, readable copy, please feel free to respond, and I'll make it worth your while.