6146's

[Glen Zook]

You can mix the 6146 with the 6146A since the
difference is in the makeup of the heater.  But, NEVER
mix a 6146 or 6146A with a 6146B.  You are definitely
asking for trouble.

The main problem with using a 6146B in place of the
6146 / 6146A is that the biasing requirements are
different for the 6146B.  Also, the 6146B can be very
difficult to neutralize in circuits designed for the
6146 / 6146A.  Collins ran into this problem with the
S-Line transmitters and the KWM-2 series when the US
Government went from the 6146W being the equivalent of
the 6146 / 6146A to the equivalent of the 6146B
without changing the nomenclature.  The neutralization
circuitry in those rigs "burned up" in a very short
time.  Since the military insisted on using the newer
tubes, Collins had to redesign the neutralization
circuitry on all equipment that was being shipped new
as well as retrofitting the equipment already in the
field.

Anyway, sometimes the equipment designed for the 6146
/ 6146A will work fine with the 6146B.  Then, other
equipment of exactly the same model will not.  If you
insist on trying the 6146B tubes, first neutralize the
transmitter.  If it won't neutralize, then replace the
6146B tubes immediately.  If it does neutralize, then
watch the neutralization for several days, if it
changes, then replace the 6146B tubes.

I know of people who haven't had a single problem with
using the 6146B tubes.  But, I also know a lot more
that have definitely had problems.

Glen, K9STH

--- Tom Byers <ByersEyecare at AOL.COM> wrote:

I think the important thing to remember is not to mix
6146's ...

=====
Glen, K9STH

Web sites

http://home.attbi.com/~k9sth
http://home.attbi.com/~zcomco

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