There are many cases where not only can you not get to the pin, you can't even see the socket.
This tool is handy for making resistance measurements and some live voltage measurements. The long wires will ruin RF functionality though.
Take a rusty tube apart. Be careful smashing glass. Drill a hole in the top to fit a grommet.
Wire each pin. I used 18 ga silicone to start with. It was difficult. Tried 22 ga. Much better but weaker.
Fishing the wires through the grommet is difficult. If I had to do it again, I'd solder 3 inch lengths
of solid wire to guide the stranded through.
Ordered an 8 position rotary switch and wired it all up.
Ta da!
I initially put the bolt on the end. Worked great while not closed up. When closed, the bolt shorted to pin 8 on the switch and caused all sorts of havoc when the radio was powered up.
After a while, I discovered that a length of strapping tape made a good loop style handle for removing the thing from a socket. Too bad you can't do that with the operating tubes.
Final version. Moved the bolt to the side. The solder lug added to the bolt is required to
connect a scope probe.
Page: /Tube_extender/Tube_extender.shtml
Last modified: Tuesday, 28 Apr 2026