[Elecraft] latest K2 serial #?

[Don Wilhelm]

Sverre.

I beg to differ slightly.  The B level boards already have the 82mH 
inductor across the same R-PAK that the TF3MA mod wants to install the 
large capacitor.  In addition, the 47k resistor is already in place, but 
the path must be broken to install his 47mH inductor.

While it is do-able on the B level board, it is not as straightforward 
as for the A level board.  To follow the TF3MA instructions as written, 
one must have the A level board.  With the B level, the existing design 
must be modified and the mod re-designed a bit.
For circuit savvy K2 owners who understand how to follow a schematic, it 
should not be a problem, but those lacking that ability should proceed 
with caution and the help of someone who can interpret the schematic.

73,
Don W3FPR

On 3/23/2016 5:30 PM, Sverre Holm (LA3ZA) wrote:
> The TF3MA sidetone mod is still current as it is in fact a modification of
> the B level board, not just the A level board, as the site states that this
> is an improvement of exactly the 47k / 82 mH A to B improvement mentioned in
> the quote below. See
> http://www.raunvis.hi.is/~matti/TF3MA/sidetone_tf3ma.html
>
> See also my mod list here:
> http://la3za.blogspot.no/p/la3za-unofficial-guide-to-elecraft-k2_28.html
> (search for sidetone), where I specify it as : "Even more sinusoidal tone
> than the mod in serial #3000+ gives"
>
>
>
> Don Wilhelm-4 wrote
>> Yes, those two mods are old, and apply only to the A level boards (below
>> SN 3000).
>> There have been improvements in the K2 sidetone incorporated into the B
>> level boards, and are also included with the A to B mod kit.
>> The changes added a 47k resistor in series with C24 (R11 for the B level
>> boards) and a shielded 82mH inductor across pins 7 and 10 of RP5.
>