[Boatanchors] 813 grid to filament short

[w5jo at brightok.net]

I don't like horizontal mounting of any tube because there are variables in 
construction of the amp, or the tube, or operation that can cause the 
problem you experienced.  It doesn't take much sag for the grid to get into 
the filament as you found.

I prefer vertical mounting with the base down, or if the manufacturer of the 
tube says it is OK then base up.  Chances are you had a tube that was 
operating differently than the other (s) which caused the grid to break or 
sag enough to touch the filament.  Good luck and hope you don't run out of 
813 tubes.

Jim
W5JO



-----Original Message----- 


I have spare tubes and the rig is back up and running. My question
was, is this a typical failure in a horizontal configuration. Some
one mentioned that this is more prone in GE tubes, and coincidentally
of the 4 this was the only GE tube, Time will tell, and so I continue
to enjoy great 15 meter conditions on AM "running full legal limit"
until I run out of 813s.

Thanks

- Paul