[Amps] HENRY 4K-U; POOF EVENT

[K8MLM at aol.com]

Amps,
 
I had a poof event on my Henry 4K-U.  Appears the tube went south...  no 
power out. I opened the amp and checked for any signs of failure or  damage.  
Found none.  Replaced the tube with a 8877 pull of unknown  quality.  Fired 
up the amp and it appeared to operate correctly ... power  output, loading, 
etc.  On the air reports said it had no abnormal  sounds... no distortion, 
sounded good at 1400 watts  output.  However, the grid current was reading 
too  high.  Checked the calibration of the grid current meter per the 
directions  in the manual... grid meter was indicating correctly.  
 
Any recommendations on what to check next?  If the tube is good, I  don't 
want to damage it.  
Could a bad tube exhibit abnormally high grid current?
 
Bob
K8MLM
Woodbridge, VA