[rd48sec]

I have a 41-290 that I am restoring for someone.  I am in the process of testing all the tubes in the unit.  I have come across a problem with the type 37, 41 and 84 tubes in this unit.  I am unable to test them in my Sencore TC28 Hybrider or B&K 747B testers.  There is no socket that fits these tube.

How can I test these tubes so I know they are good/bad?  Is there an adapter socket out there?  Any help/knowledge is appreciated.

[radiodale]

There is a ham radio club in your area. Someone will have the correct tube tester.

https://www.ecarc.org

[morzh]

Or if you are serious, buy a decent tester. A Hickok 600A would do.

[Chas]

There could be octal equivalents for each of those tubes. Find known dead glass tubes with the octal base and pins needed to test the equivalent type. With octal sockets, wire from the pins of the old tubes to the equivalent salvaged octal tube base...

Saves buying an up dated tester. Some of the pin configurations may be the same so maybe three or two adapters needed...

Most online tube sites will have the characteristics knowledge to make the substitution. for test purpose the current rating of the filament may not be important.

The process will help expand tube knowledge...

"Teach a man to fish...."

[Phlogiston]

The 747 is a good tester, I don't know about the other one.

Yeah, find someone with a good MC tester. Most of the Hickoks will do those.

[rd48sec]

Thanks for the advice. I stopped in at my local electronics service place. They were able to test the tubes.

Both my type 41's are bad.