I'm probably one of the older members of this forum! I've been interested in old radios for like 70 years.
I had an early 40's Arvin 4 tube radio. It worked rather well! One day it quit working, so I took the tubes to the local TV shop and had them tested. The 35Z5 had an open heater! A new 35Z5 was $1.35 which I didn't have, so the radio got trashed!
A year later, I found out, you can put a jumper wire on pins 2&3 and the tube can be used for a while! :thmbsp:

Isn't wisdom and experience wonderful?

wow! Ive so wished I could have been born in 1920 instead of 1960s...I would have been in the prime tube world of electronics! 1 dollar and change for a tube!