I should know the identity of the TO3 tomorrow , both NPN on rechecking.
Loose Collector bolts so I have to get to the other side to tighten. Not
rivets , looked superficially like aluminium rivets . On Googling ,maybe cct
similar to this admirable effort at unravelling to a schematic, the Stingray
amp

http://ax84.com/bbs/dm.php?thread=467875