[Johnson] Surge protection for Johnson BA's

[Brian Carling]

All of the Johnson rigs I have used made that scary THUD when you turn 
them on.

What is this "device" that you put in line, please?

C Eus wrote:

>All:
>During the final testing of my Viking 2, I noticed a
>pronounced "thud" whenever I hit the filament toggle
>switch. The "thud" is a manifestation of some large
>amount of instantaneous current as it hits the primary
>of the power transformer. As AC comes in, your not
>guaranteed that the waveform will come in at any zero
>point of AC waveform. It could be at a max of 115 VAC
>while the primary doesn't have some resistance or
>reluctance to stop the incoming current flow. 
>
>I suspect enough of these "thuds" over the lifetime of
>a BA will eventually cause it to fail. After hearing
>that sickening "thud" for so many times, I decided to
>do something about it. I bought some surge protection
>devices on ebay. I already used on on my S-40 (in
>addition to putting an inline fuse with the cord). In
>the case of the Viking 2, I took the jumper from one
>of the filter coils to the fuse and in its place in
>went one of the surge protection devices. After
>installing the device and trying the filament switch
>again, no longer were the "thud" sounds of inrush
>current were heard! It didn't affect the performance
>of the Johnson and needless to say, this is one
>transformer that I don't think will see the light of
>"P.Dahl's Day". 
>
>For more info on these units, please refer to the
>following URL (put out by Canadian Ham Jan Skirrow of
>"Boatanchor Dreams" fame).
>http://skirrow.org/Boatanchors/TechTalk3.pdf
>
>73 de Cal, N6KYR/8
>
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