[Kenwood] TS-520/TS-520S Neutralization

Sat, 24 Apr 2004 01:44:38 -0400

Eyes getting bad: 5146A = 6146A

From: "Larry, K4WLS" <[email protected]>
Subject: Re: [Kenwood] TS-520/TS-520S Neutralization

6146W's are NOT a direct replacement for 6146B's. The
6146W's are the miltary version of the 6148B. Nice thing
about the 6146W is they are built to Mil Specs and are more
rugged than the 6146B. They were originally conceived to
run in the old military VHF equipment. Big problem, the plate
dissipation power of the 6146W is only 75W compared to
90W for a 6146, 5146A, and 6146B.

The 6146B has a plate dissipation power of 90W, so two
of them in parallel can be run at 180W input on CW.

The 6146W only has a plate dissipation power of 75W, so
two of the can be run in parallel for 150W input on CW. If
you are running 6146W's better lower the Drive Level on
CW or the Mic Gain on SSB. Otherwise you are risking
lowering the life of the tubes, failure of a tube, and associated
damage to other components in the finals, especially the
sreen grid resistors.

Plate Dissipation Power (Power Input per Tube) = 1/2 Ip
(total plate current - actually cathode current minus screen
current) X (plate voltage or key down HV on meter). This is assuming both
tubes are perfectly matched and are conducting the same amount of current.
Unless you have a matched pair of finals (which you should always run in
parallel power amps), most
likely one tune is conducting more than the other. All the more
reason to stay away from 6146W's.

If you have 6146W's in your rig, tune up on CW and advance
Drive Level to 225 mA (180W input with key down HV of 800V).
Hold key down one or two seconds and watch Ip start
dropping. Hold key down longer and listen the the crackling
as the plates start getting very hot as the plate dissipation
power is being exceeded. If rig covers were off, and final
cage removed, hold key down a bit longer and watch the plates
start glowing cherry red as the crackling due to heat gets more
intense.

If your key down HV is more than 800V, do Ip = Key Down HV/
180W to get the Ip to advance the Drive Level to, to try this little
test on 6146W's.

If you use 6146W, they only good for 150W input - you should
always run a matched pair of 6146B's in your Kenwood tube
rigs for best performance.

Also, you most certainly can use a 6146 or 6146A as a
replacement for a 6146B in all TS-520 thru TS-830S as
long as the tubes are good.

You guys need a good Transmitting Tube Manual such as that
put of by RCA or GE, EIMAC - they are still in print.

Larry,  K4WLS

From: "Ray Friess" <[email protected]>
Subject: Re: [Kenwood] TS-520/TS-520S Neutralization

Don:
I also have a ts 520 .... two of them in fact.  I recently retubed the
finals in one of them using
6146W tubes and have had no trouble with neutralization once done.
The 6146B is the American version of the finals that come with the
Kenwood, and you can use
6146 W in place of 6146B, but NOT for a 6146 or 6146A...
Ray wa7itz

Donald E. "Buck" Stiles wrote:

>Kenwood listees,
>
>I needed replace the tubes and my TS-520.  I have a 6146W tubes available,
>however, I am concerned that I will not be able to neutralize these tubes.
>The normal tubes are the 6146/6146A variety.  Has anyone had experience
>neutralizing the 6146W in the TS-520/TS-520S?
>
>Any suggestions appreciated.
>
>73 de N8CSP k
>
>
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Your moderator for this list is:
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