@tggzzz: apparently you can just remove the power supply and valve from it, swapping for a 9v battery, stuff a 2n3819 across the base of the socket and stick a resistor across the anode resistor to bias it and it'll work as well if not better than the original. I have 3 more of these on the way so the plan is to convert at least one. Total plan is:
1. Museum grade restoration.
2. Museum grade restoration and conversion to FET.
3. Turn into regen receiver.
4. Parts mule.
@VK5RC: my eldest two are the same. Only ever see them if the WiFi is down