7 and 9 pin valve extenders
for testing thermionic circuits in hard to reach places.
and testing of some ex military radio gear is sometimes very hard
because the circuitry under the valve is heavily obscured. These simple
to replicate tools permit probing of valve elektrode voltages.
attempt any RF alignment of high frequency circuits with the
valves on extenders. The extra capacitance may render your adjustment
void and on some RF circuits also permit unwanted oscillation.
is self evident from the pictures. I had some old ceramic
material sockets on hand, so thats what got used. The extender pins are
tinned copper wire that is about the same diameter as a standard 7/9
pin valve. Secure the extender pins with perspex or simpler
still, a blob of polyester resin.