I only recently began servicing my own gear thanks to all the help and info I got here
Most of it is not rocket science but I'm good at mechanics in general and obsessive compulsive and neurotic. If you get the right service manual and are careful taking things apart and keep everything in order and make sure nothing can fall off the work bench and get lost then, hey, no problem! The US Divers manual I downloaded didn't have specific instructions (maybe it did, not sure) for adjustments but I downloaded a Sherwood manual and it DID have fine tuning info, much of which applies to single-hose regs in general. I also have a Dacor manual (hard copy) that has been extremely useful. I got it from a guy selling old Dacor gear on Craig's List. Perhaps the trickiest part (for me, anyway) is knowing what to lube and what not to lube and with what. BTW I think my old US Divers reg is not a Calypso IV afterall, but looks the same inside.
Like I said, I have two old US Divers regs and one of them (probably the one that is not the Calypso J) has a very small exhaust port and purge valve. The other one has a slightly larger port and valve and is A LOT easier to exhale from. That's the one I actually dive with.
I didn't catch the vintage bug, it caught me. This just happens to be the stuff I've been diving with all these years, except for the Sherwood regs and a couple of aluminum 80s. But now I feel obligated to try to restore my old tanks to their original appearances but I'm having a hard time finding and pics from the right era.
At Pac sounds familiar. I guess I'll have to look it up. Somehow it has negative connotations in the spiderwebs of my mind. Hope not for your sake.