I have recieved back from Gary Bleisch the Sprint 276 Pro Manta Ray F/S model manual. As with all Sprint manuals it's pretty generic but does have a wiring diagram in the back. If any one thinks they can use this manual, I'll ship it on loan, but will have to ask for it back. It's the only manual that I have in possesion now but I am constantly looking for any out there to share.
We do also have a wiring diagram for a 286 Pro stickied below. Thanks to the current and former Sprint owners for sharing.