Last night I aligned all the bands, first on receive and then on
transmit. On 10m, when doing the receiver pre-alignment, I couldn't seem
to detect any audible change in signal level as I adjusted L12 and L13,
which worried me. But when I did the transmitter alignments I had no
trouble getting 2
Owen,
That bit of funny procedure for setting L8 and L9 first on 20 meters
(while the capacitors are set to the mid-point) is an interim step that
only needs to be done once (unless drastic changes are made to the
30/20m bandpass filter). It assures that the L8 and L9 are set to
somewhere
Owen,
You should not need a signal generator for Transmit Signal Tracing - I
believe you are in the Receive Signal Tracing area - skip that and go to
the Transmit Signal Tracing. The K2 itself is the signal generator for
this TX signal tracing.
Try increasing the CAL CUR setting to 3.50
Hi Don -
OK, I have gone through the transmit signal tracing steps and found a
couple of anomalies. I'm referencing the specific section name and
step number in the troubleshooting here.
ALC:
3. Pin 2 of U8 (on the control board) shows 4.97VDC instead of the
expected .7 - 2.5VDC. The
Owen,
I tried to caution you not to get excited about RF voltage values that
were higher than the listed expected values.
That is normal for a K2 that is not detecting any output - the K2
increases the drive in an effort to obtain more output. Since you have
no output, the RF voltages on
Ah, so you did, Don. My mistake for not taking heed, I would have
pressed on with the signal tracing. However, while sitting here at work
and pondering the problem, I just re-read your message below for the 3rd
or 4th time, and something clicked: AHA! I _did_ put C6 in the wrong
holes!! When I
Owen,
I will have to take some of the blame about the wording in the manual
errata sheet. I had though specifying the outer holes of the set of
three was sufficient - but I was apparently thinking only of a set in
mathematical language terms (I am certain any mathematician would select
the
Well that did it! I verified that I put C6 in the wrong two holes,
corrected it, and now I'm getting good power out on 40m! Thanks Don!
I'm still seeing only .3-.4 watts on 12m and 10m, but I realize I'm
getting ahead of myself. Should I just proceed through the alignment
until I get to
The latest errata has a picture! You know -- something about a thousand
words...Hi!
It will be on the web site soon. My apologies for not having it in time to
save you the work Owen.
73,
Ron AC7AC
-Original Message-
Owen,
I will have to take some of the blame about the wording in
Owen,
Go through the transmit alignment for the bandpass filters before
declaring another problem.
Most K2s will have some power reduction on 12 and 10 meters, but if your
10 meter power output is greater than 10 watts it is OK.
73,
Don W3FPR
On 10/6/2010 10:16 PM, Owen B. Mehegan wrote:
Hello -
Two nights ago I completed the assembly of my K2's RF board, and after
a visual inspection verification of resistance checks, I assembled the
radio per the instructions and began the third phase of alignment and
test. I've discovered a problem right off the bat, though. In the 40
Owen,
I am going to assume that you were successful with the Alignmant and
Test Part II and were able to receive 40 meter signals. If not, you
need to backtrack a bit and get receive working first.
The easiest way to troubleshoot a lack of power output problem is to
do Transmit Signal
@mailman.qth.net
Sent: Tuesday, October 05, 2010 10:01 AM
Subject: Re: [Elecraft] K2: Debugging low transmit power
Owen,
I am going to assume that you were successful with the Alignmant and
Test Part II and were able to receive 40 meter signals. If not, you
need to backtrack a bit and get receive
Hi Brian -
I haven't tried transmitting on any other band yet, but your
description of only getting about .5 watts out when you tune, and L1 and
L2 having no effect on this, mirrors my own.
Tonight I will begin tracing the circuit with the RF probe. I also have
access to some more sophisticated
Brian,
Even though Owen's outward symptoms are similar to yours, the failure
point is likely quite different.
That is why Transmit Signal Tracing is important. There are 5 active
devices in the transmit chain as well as the bandpass and low pass
filters, and the oscillators (VFO and BFO)
Thanks again for the suggestions Don. Tonight I started doing some
signal tracing, and my RF probe seems to work fine with my DMM.
However, I ran up against a different obstacle: I don't have a signal
generator handy, and the LPF/BPF/T-R Switch tests seem to require one.
I can get access
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