[Elecraft] Checking KPA relays

[Don Wilhelm]

Jerry,

Yes, do check the LPF and relays first just as a 'confidence builder'.
If that is all working fine, then I would first direct you to the 
wattmeter section.  Check with an external wattmeter in-line.  If the 
output power is in excess of 100 watts no matter what the requested 
power setting, then the KPA100 wattmeter is not working (D16 and D17 
usually is the problem).  Once you obtain proper power level control, 
then other problems can be addressed if necessary.

73,
Don W3FPR

n0jrn wrote:
> Thanks Don:
>
> Easy enough !           I appreciate that very much.
>
> Yes I am working with my KPA100.  I'm looking for why the K2 drops out of TX 
> when I try to adjust output above 35 watts.
>
> A couple of the bands are also showing excessive current draw and high 
> reflected.
>
> Just wanted to check the relays and make sure everything in the LPF first.
>
> I've spent a good part of the evening reading the archives for similar 
> issues.   Your comments in most cases take folks back to the SWR bridge and 
> related components.
>
> BUT         first things first !
>
> Have a great evening
>
> Jerry
>
>   
>> I assume you are working on a KPA100 - if not, please ignore.
>> The easiest way to check the relays and the LPF of the KPA100 is with an
>> antenna analyzer.
>> Put the KPA100 to the right of the K2 (upside down on a book or other
>> support) with the ribbon cable connected to the K2.  Power only the base
>> K2 through the coaxial jack.
>> Put the leads of a 50 (ok, 51 will do fine) ohm resistor into the
>> connector that normally connects to the AUX RF header.
>> Power the K2 on and select each band in turn.  For each band, scan
>> through the frequency range of the antenna analyzer to determine the
>> cutoff frequency for the LPF - it should be higher than the band edge,
>> but lower than the 2nd harmonic.
>> If all bands meet that criteria, the relays and LPF are correct -
>> assemble the KPA100 to the base K2 and go.
>>     
>
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