[Amps] Triode grounded grid amp strange failure

[Jim Thomson]

Date: Tue, 14 Jul 2015 17:21:26 -0700
From: "Dave Hachadorian" <k6ll.dave at gmail.com>
To: <amps at contesting.com>
Subject: Re: [Amps] Triode grounded grid amp strange failure

This type of thing can happen if B- and ground are tied together. 
There should be a beefy diode between B- and ground.  Sometimes 
this diode can short if there is a high current glitch event. 
Also, the plate current meter may have blown open during such an 
event.

Dave Hachadorian, K6LL
Yuma, AZ

##  use RVS connected 6A10s..... between B- and chassis. This ensures the B- can never float
more than + / -  .7Vdc  from ground.    Parallel several  6A10s to increase the peak current ratings.
Use a HV fuse, in series and  before the 50 ohm glitch R.  The 50 ohm glitch R limits the peak fault 
current to a safe value.  The fuse interrupts the fault current..and in less than 2 msecs.  A suitable glitch
R can be made using large globars..or  2 x 100 ohm, 225 watts WWs  in parallel.   Put some more rvs connected
6A10s  across the grid and plate meter. 

Jim  VE7RF