but . . .but . . .BUT . . .BUT your " S " is being a " 5"
AND . . . . your actual designer and original part manufacturer is declaring it "obsolete" and has no faith in even recommending a like substitute replacement for it.
( That is being one HELLUVA spec in a TO-220 package anyways. )
So, with my recent Rockford Fosgate plight, I thought I'd practice my google-fu a bit on this one as well. Unfortunately, I don't really have the brains to tell apples from androids when it comes to the intricacies of transistors..