[Elecraft] K1 no output on 20m

[Rod N0RC]

John,

On 20m, are you getting output from the premix stage on the RF board? At
pin 4 or 5 of U7 you should have a "healthy" signal at 19MHz, See
Appendix E, "Receiver and VFO Signal Trouble Shooting", page 5, of the
main K1 manual for details.

If the 19MHz signal is NOT present it is possible X2 on the filter board
has failed.

If the 19MHz signal is present, it is more likely that a problem exists
in the Premix Band-Pass filter. More signal tracing as outlined in the
manual should isolate the problem.

Before doing all the testing/signal tracing--inspect your soldering of
X2, C3, C4, K2-pin 5 and K4-pins 4&5, all on the filter board. Look for
trace-to-trace shorts, and cold solder joints, reflow questionable ones.

The parts I listed above are all unique to the 20m
premix-stage/premix-BP filters. The symptoms you mention are consistent
with the Premix circuits not working.

GL
73, Rod N0RC



----- Original Message ----- 
From: "John Pfeifer - KL�WN" <qrp@johnpfeifer.com>
To: <elecraft@mailman.qth.net>
Sent: Sunday, August 03, 2003 2:25 PM
Subject: Re: [Elecraft] K1 no output on 20m


Hello again,

After posting my initial message, I decided to do some "Cheap 'N Dirty"
signal tracing as described by Tom Hammond(N�SS).

I have a KFL1-4 filter board set up for 40m, 30m, 20m & 17m.

I used a 15ft length of wire with a 550pF blocking capacitor.

At test point #1 (RF Board, T1-1, input winding of the transformer
feeding the mixer), I got clearly discernable signals on 40m, 30m & 17m.
No change detected at all on 20m.

I tried a few more test points for all bands and--once again--signals
were present on all bands except 20m.

...
Any ideas?