[Elecraft] Re: KG4DNI: K1 status problem on 20m: KFL1-4 !!!FIXED!!!

[Daniel L Brinneman]

Hello everyone,

All your helps were appreciated.  I am therefore writing this message so
a future tech searching the archives may get their answer.

Symptoms of Elecraft K1:
--All bands work except for 20m. 20m shows 0.1Watts out on TX with no
change as the WPM+/- are tapped. Even though the power 'Out' menu is set
to 2.0Watts.
-20m shows no RX noise increase even with antenna connected.
-15m and 20m may have no RX, but the other two bands will have great RX
and TX. But 15m will put out power on TX, not 20m.
--Using the RF probe with the digital voltmeter set to a DC scale: all
bands show approximately (+/- 0.1VDC) equal voltage on TX in/out of the
RF BPF, but on 20m the voltage reading drops [~0.2VDC at P2-1 on the
KFL1-4 --> to a reading of ~0.035VDC at P2-8 on TX after the fixed
capacitor C17]. ~0.2VDC measured on TX with the RF probe at P2-1 is
~7Watts out on all bands.

How to fix it?
Adjust 20m PREMIX and RF Band Pass Filters varicaps (variable capacitors)
on RX with ANTENNA connected.  Set your K1 to a known frequency that is
someone is currently TXing on.  Then adjust the varicaps for the loudest
RX noise,  leave those caps alone.  Then proceed to the TX Alignment
procedures of the K1 for the filter board.  Last tweak all bands on TX
with an external calibrated wattmeter.  The wattmeter will allow you to
visually verify that you have power out on 20m.

Now if you have no doubt about your soldering skills and have checked and
rechecked the board and looked for  cold solder joints (gray looking,
instead of shiny silver) and/or solder bridges, the K1 should now have
the sweet sound of CW coming through the speaker or your headphones. 

I would like to thank the group, Gary Surrency, Lisa@Elecraft, and Scott
King for their patience in helping me fix this problem and talking to me
on the phone.  This is my first K1 built for a friend.
Daniel
kg4dni

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