[Johnson] My poor sick Viking II

[KENNETH A CRIPS]

I have been watching My Viking II transmit while dumping it's output into a
cantenna trying to track down the fuse blowing problem.  I replaced the 
807's
one was gassy, the other was weak. I pulled out all of the 6146 (not A, B, 
or W)
I had and tested for the two best ones. Here is what I witnessed.
The transmitter was in CW mode, 160 meter coil switched out, M122 VFO 
installed.
I started into the tune up and the PLT  dips where coming at the correct 
places
for the frequency I was set at. I made sure the PLT reading never went above 
250 mills.
as I approached the tuning peak the meter started to slowly raise. I had 
lots of fuses so I watched the tubes to see if anything happened. I had a 
R390A on the frequency the
transmitter was tuned to.  I noticed a increasingly loud buzz, and at the 
same time
one of the 6146's started to arc inside and with in a second or two the fuse 
would blow.
I changed out the 6146 that was arcing and started again the same thing 
happened except this time the tube that I had not changed arced over. I am 
going to check the clamp
circuit on the Viking again I set it up and it should be ok, but who knows 
with old gear like this.

Do any of you have any ideas what is going on here.

                   Ken de W7ITc