[TMC] FRR receivers and testing 4CX tubes

[H. L.]

I am very pleased to have discovered the TMC group.  Your archive is 
a wonderful resource.

I would like to find a TMC FRR-type of single-channel receiver, 
preferably with a FRRD-5 plug-in tuner. If anyone has one available, 
please let me know.

I am in the slow process of restoring to operation an AM TMC station, 
consisting of a GPE-1A exciter and a PAL-500 linear. Up to now I have 
only operated a Collins KWM-2 barefoot SSB, but now everything in the 
station has to be upgraded to handle the extra power and space. Quite 
a challenge!

One question: has anyone figured out a way to test a 4CX250 or 4CX350 
with an ordinary tube tester?  I know that the only real test is in 
the amplifier, itself, but I would like to conduct crude tests or 
comparison of used tubes without firing up the big amplifier and 
unplugging its output tubes. The 4CX's 6.0 filament voltage can be 
achieved with a Variac to drop the usual 6.3 Volt setting without 
upsetting other readings by too much.  And, I would guess that, by 
means of a socket adapter, the tester could be "fooled" into checking 
one of these tubes as if it were a standard tube listed on the 
tester's roll.

Hal, kk6hy at arrl.net