Well....while Henry has ceased making amps, they still have their import and repair business. In fact, they used to offer (maybe still do) replacement boards for the early mercury rectifiers. In the least, it is worth a try.
Geez, I'm like Steve, in that I can't remember the last time I saw one with tube rectifiers. Perhaps you should advertise it on ebay as an original and sell it for lots of bucks. Then you could buy an Alpha which if you keep it long enough, will be worth what the Henry is in collector value. Maybe!