[Elecraft] (KX1) - Question of Power Modification Timing

[stan levandowski]

Don thank you for this rapid and complete answer.  I'm printing this 
email out to include with the KX1 documentation. I'll always be using 
either the internal AA cells or a dedicated 12VDC wall wart so I think 
I'll just install the mod now and avoid de-soldering.   

73 and Seasons' greetings,
Stan WB2LQF


On Sun, Dec 18, 2016 at 06:35 PM, Don Wilhelm wrote:

> Stan,
>
> The information in the Power Mod instructions is correct.  SOME KX1s 
> have lower power output than others due to component tolerances.  Ni 
> some cases, this becomes more of a problem with the KXB3080 
> installation.  I would not arbitrarily install those resistors.
>
> Install the KXB3080 option and then test all bands using a 13.8 volt 
> power source.  If you can achieve 3.5 watts on all bands, that is all 
> the design point offers.  If one or two bands are lower, first try 
> adjusting the spacing of the green turns on L1 and L2 to see if you 
> can even out the power.
>
> If you cannot achieve 3.5 watts on any band, then install the power 
> mod.
>
> I must add that the heatsinking of the KX1 and the rating of the zener 
> diode in the PA stage are not designed for more than 5 watts.  If you 
> are getting more than 5 watts on any band, turn R1 to a lower level to 
> limit the power to 5 watts.
>
> If you will always be operating on a voltage less than 13.8 volts 
> (battery operation), you may want to install the power mod anyway.
> The actual power output will depend on the power supply voltage.
>
> 73,
> Don W3FPR
>
> On 12/18/2016 6:12 PM, stan levandowski wrote:
>> I'm building my second fully optioned KX1.  I built one a few years 
>> ago
>> with no problem and it was great. I sold it when I bought a KX3.   I
>> missed it so much I just bought myself another one.
>>
>> But I could use some advice because something doesn't make sense to 
>> me.
>>
>>
>> I opened the 30/80 meter parts package and found a "Power Output
>> Modification Kit" for the KX1.  It consists of two resistors:
>> replacements for R11 and R30.
>>
>>
>> I have not yet installed the "original R11 and R30" so can I just
>> install these power mod resistors NOW to avoid future de-soldering?
>>
>>
>> This sounds like a dumb question, I know, but it seems that if this 
>> has
>> been a known problem for the KX1 since April 2006 (Revision B), why
>> weren't the kit resistors upgraded a long time ago, or made an 
>> addendum
>> to the KX1.
>>
>>
>> Why were they in the 30/80 module kit?  What's the connection? Do the
>> upgrade resistors only apply to the 30/80 mod?
>>
>>
>> If I had not ordered the 30/80 mod, I would not have known about this
>> power mod.
>>
>>
>> 73, Stan WB2LQF
>>
>>
>>
>>
>>
>>
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