[Boatanchors] Question about testing tubes

[David Stinson]

Be careful when "blasting" tube cathodes.
The "blasted" old cathode stuff can go unwelcome places.
I have a 211 that had no emission.  I "rejuvinated" the 
cathode and got it back up to working standard, but
got "out of sequence" and popped B+ to it with the 
fil still very hot.  Boom---- cathode coating on the grid,
and nasty grid emission.  I've been thinking of getting
it hot and "reverse-blasting" by hooking B+ to one
side of the fil.  Nothing to lose by trying...