What do you mean by non-functioning? How does a tube not function? HAH, Unless that was the one I sent back for replacement do to unaligned threads in the cap.
If you want a fun project, go for it ! It's pretty damned tough, though - CNI has some serious skills in making them - and it's pretty tough to fix one that is screwed up !
Someone like IgorT would probably LOVE that broken CNI, the drivers in those things are close to perfect! Man if I wasn't broke right now I would be all over that.