{Collins} Re: Fwd: Re: 6146B Neutralization technique



If one has a lot of spare 6146s, then Neutralization shortcuts
can be taken.

One of the characteristics of a poorly neutralized Final is
that the grid current drops as the plate current is dipped.
(But, who watches both currents?) I learned that the hard
way on my old un-neutralized DX-100 (vintage 1956).

If you've never seen that little red glow on the side of the 6146
plate turn white and burn through, then you've been visually
deprived.

That's why the KWM-2A Instruction Book has three steps for
Neutralization, being PA, Driver, and Feedback, in that order.
When one is done, all should be done.

John Painter
W5LQS

----- Original Message -----
From: "Roy Morgan" <roy.morgan@xxxxxxxx>
To: <collins@xxxxxxxxxxxxx>
Sent: Friday, July 23, 2004 11:26 AM
Subject: {Collins} Re: Fwd: Re: 6146B Neutralization technique


At 03:42 PM 7/22/2004 -0700, Greg Mijal wrote:
>I just neutralized my Heathkit Marauder after a tube change with a very
>simple technique.
>Switch to 20m band
>Pull the plate rectifer.
>Stick your scope probe into the body of the final coil.
>Key the radio and tune for minimum output on the scope.
>It works FB here

Would be short cut takers,

BEWARE: I the screen supply is separate from the plate supply, that is not
from the same source, you can burn up the screens.  Running a tube with
screen voltage and no plate voltage can cause excessive screen current.

Transmitters such as the one kilowatt-class TMC GPT-750, and many marine
transmitters derive the screen voltage from the plate supply. The S-line is
not the same, and has the screens supplied from the low voltage B+,
normally via a jumper across two rear panel Jacks.

Roy

- Roy Morgan, K1LKY since 1959 - Keep 'em Glowing!
7130 Panorama Drive, Derwood MD 20855
Home: 301-330-8828 Work: Voice: 301-975-3254,  Fax: 301-948-6213
roy.morgan@xxxxxxxx --

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Nets: Tues: 3.805 Mc-2000 Central / Thur: 3.875 Mc-2000 Central
Fri: 3.895 Mc-2000 Pacific / Sun: 14.263 Mc-2000 UTC
1st Wed (of the month) AM Net 3.880 Mc-2000 local (ET, CT, MT, PT)
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