When I tune it there is that telltale pinging going on like the string is hanging up in the nut or at the bridge. Tonight's job will be some fettling with a needle file and some application of graphite via a pencil lead.
Mod fever vs patience
My acoustic guitar player's "Grip OF Death" was throwing my notes sharp and making me crazy. After putting my SG in the hands of an excellent electric guitarist, and listening to him play my Gibson and sound awesome, I realized it was nothing wrong with my SG.