[Johnson] JV II Signs of life (death?)

[Glen Zook]

Sounds like the 6146 was shorted.

Replace both of the 6146 tubes with either 6146 or
6146A/8298 and the 5R4 with any of the 5R4 types.  You
can also use 6293 tubes.

Avoid the 6146B/8298A and any 6146W with a code date
of 1964 and later.

If you haven't read the article on the 6146 family of
tubes that was in Electric Radio a while back (and has
been republished in several other publications) go to
either of the websites that are listed at the end of
this message.

The vast majority of transmitters that were designed
for the earlier versions of the 6146 are not "happy"
with the 6146B which is a completely different tube. 
A minority of transmitters will work fine with the
6146B/8298A and 6146W after 1963.  I have had 3
transmitters with serial numbers within 10 of each
other.  The 6146B worked in 1 and not in the other 2. 
It depends on a lot of things, primarily how the
component tolerances "add up" as to whether or not the
6146B will work.  Read the article and then you will
know where you are going.

If you mean the Johnson Valiant II instead of the
Johnson Viking II, there are 3 6146 tubes in the final
amplifier and 2 in the modulator.  The 6146B will work
fine in the modulator so long as both tubes are 6146B.

NEVER mix a 6146B type with the earlier types in the
same circuit.  You can mix the 6146 with the
6146A/8298 since the difference is in the heater
circuit.  But NEVER mix a 6146B with either of the
earlier versions.  This is really asking for trouble. 

Glen, K9STH


--- Rich Soennichsen <rsoennichsen at gmail.com> wrote:


I threw the switch and this time watched the tube
side, no smoke this time but after a few seconds the
same terrible noise and the VR9 (5R4) and one of the
6146 (V7) tubes were putting on a light show of purple
light.  Of course I only let this go on for a second
or two.









Glen, K9STH

Web sites

http://home.comcast.net/~k9sth
http://home.comcast.net/~zcomco

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