[R-390] I Hope Everyone Is Happy Now....

[DJED1@aol.com]

Maybe if I had a couple of dozen R-390As on hand, I'd wory more about these 
tubes.  For my solitary radio, I've got a spare 3TF7, and a pair of 26Z5s.  
the radio has been operating for 25 years with a homemade resistor in place 
of the 3TF7, and the original rectifier tubes.  So let's see- in another 25 
years my kids can plug in the 3TF7 and sell the radio on e-Bay for about the 
price of a new car, or they can keep the radio, continue with the resistor 
and plug in a 26Z5 as needed.  So I figure the spares I've got are good for 
at least 2 more generations.  Seriously, I think I've replaced a total of 3 
tubes in 25 years of light duty listening.
Way back when, before the internet, I couldn't find a spare 3TF7 when the one 
in the radio died.  I cut open the top of the tube, pulled some nichrome wire 
from an old wirewound pot, and wrapped the wire around the glass envelope.  
This homemade resistor has been working for at least 20 years.  Who needs a 
high-vacuum pump anyway!
Ed