[Amps] TL922 Repair question

[Georgens, Tom]

Hi All -

I am looking for some advice on the repair of a TL922A.

I had been checking out a TL922 that I had not used in a year, when it
developed a problem.  When tuning up on 15, the power suddenly dropped for a
second and then one of the fuses blew.  After replacing the fuse, the amp
came back on but the output would not go much over 400W.   It seemed like
only one tube was actually being used.  As it turns out, when I looked at
the tubes during transmit, only one of them was turning red.

When I opened the amp, I did not see any obvious damage and I planned on
replacing the tube with a spare that I had.  Before doing so, I decided to
look under the tube.  What I found is that one of the coils between the grid
and ground looked melted (but not burned) and was no longer a DC short.  

My question is what may have caused this problem.  Did the coil merely fail
(I vaguely recall replacing one of these before) or could something else
have failed, such as the tube, that caused the coil the fail.  

The complication here is that the amp is in Barbados so I cannot do any
further diagnosis and I must bring down any spare parts that I might need.
Therefore any insight prior to my next trip would be appreciated.

As a general comment, I was surprised to see this method of grounding the
grid.  Is there a better way to do this that I should consider.  

73, Tom W2SC 8P1A