Posted by
omehegan on
Oct 06, 2010; 9:31pm
URL: http://elecraft.85.s1.nabble.com/K2-Debugging-low-transmit-power-tp5601987p5609119.html
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 realized you were specifically referring to a strip of 3
holes it jogged my memory. There's even an errata about this, which I
dutifully added to the manual, but it still confused me. The errata
says:
Add to the end of the step, "Use the outer of the three holes, not the
two holes closest to the left edge of the pc board."
Somehow I just interpreted that as "use the two holes closest to the
right edge." Since I'm at work at the K2 is at home, I thought I would
have to wait to confirm my mistake, but I remembered that I sent some
friends a picture of the board when I finished it. I just pulled it up
in my email, and I can clearly see that C6 is in the wrong holes!
I'll correct this tonight and see what that gets me. Thanks Don!
On Wed, 06 Oct 2010 13:29:17 -0400, Don Wilhelm <
[hidden email]>
wrote:
> 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 the working stages will be at the
> maximum value.
> The listed "expected" values are within 10% of what is to be expected
> for a properly working K2 at 5 watts.
>
> The transmit buffer has output and there is none at W6. Look at the
> schematic so you can identify the components between those two points.
> Basically it is the D6/D7 switch and the bandpass filter.
>
> Is there any chance you put C6 in the wrong holes? In the set of 3
> holes at the J15 location, the center hole should be empty. C6 goes
> in the holes for pins 1 and 3.
>
> 73,
> Don W3FPR
--
Owen B. Mehegan (
[hidden email])
"He is a dangerous mixture of sophistication and recklessness which
makes one anxious about his influence on other boys."
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