K1 Transmitter Output Problem

[Ricky Robbins]

Building a K1, thought I was on the home stretch, but I've hit a snag.
 I was on the transmitter alignment section, page 19 of the K-4
additional manual, and all went well for 10 Mhz and 7 Mhz.  I switched
to 21 Mhz and didn't get the two watts out, but got P0.1 (like the
first steps of the Alignment and Test, Part II on page 46 of the K-1
manual when the filter board is not installed).  It didn't vary, just
P0.1.

I checked the "out" menu setting and it had 2.0 watts.  I switched
bands back to 7 Mhz, and now it only has 0.1 Watt output for tune no
matter the "out" menu setting; the same for 10 Mhz.  All frequencies
appear to be within the allowed band (didn't move the VFO knob from
the starting mid position during this time).

Left it to start typing this question, wanted to go back and look at
exactly what the display read and all bands but 21 Mhz would now
output okay -- 21 Mhz still just P0.1.  I went ahead and completed the
tune-up, skipping 21 Mhz (but starting with the 21 Mhz caps for 14
Mhz) -- wanted to try the radio out and will be using it on 40 meters
for now.

Finished the work (speaker, etc) and hooked the rig up through a tuner
to a dipole tossed into a couple of trees and, for the first time in
26 years for me, made a contact (my code skills, even with some
practice recently, are woefully rusty).  After the QSO I did some
cleanup and rearranging (included unplugging the K1), then brought it
back up to try for a second contact; back to no output, if I go into
tune I get P0.1 on screen, if I try and transmit, no power out.

Any insight would be appreciated; probably (hopefully) something
simple I'm missing.  First contact was a thrill, hope to get the
second before another 26 years go by.  :)

Thanks for any help,

Rick
N4YQP
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[Don Wilhelm-4]

Rick,

Intermittent operation like that usually means that there is a poorly
soldered connection somewhere in that K1.  The other thing that will
often behave similarly is a badly tinned toroid lead.

So take a close look at the soldering.  Do all the solder connections
taper off to an almost invisible line on both the solder pad and the
component lead?  If not, that solder connection should be viewed with
suspicion.  Also look for "balls of solder" on the component leads - if
the solder looks like a "ball", two things are likely present - 1) too
much solder was applied, and 2) the solder pad was not adequately heated.

Re-flow the solder with a hot soldering iron - 700 to 750 deg F.  If
there is too much solder, use solder wick or other means to remove the
excess.  If the solder fills the thru-plated hole, that is sufficient,
but I like to see a small fillet around the leads.  Again, the solder
should flow out entirely to cover the solder pad - if you can see a
distinct line where the solder stops, that is a suspect connection.

With the toroid leads, examine the solder side - if there is a visible
ring around the wire, the lead was not properly tinned, remove the
toroid, strip and re-install.

73,
Don W3FPR

Ricky Robbins wrote:

> Building a K1, thought I was on the home stretch, but I've hit a snag.
>  I was on the transmitter alignment section, page 19 of the K-4
> additional manual, and all went well for 10 Mhz and 7 Mhz.  I switched
> to 21 Mhz and didn't get the two watts out, but got P0.1 (like the
> first steps of the Alignment and Test, Part II on page 46 of the K-1
> manual when the filter board is not installed).  It didn't vary, just
> P0.1.
>
> I checked the "out" menu setting and it had 2.0 watts.  I switched
> bands back to 7 Mhz, and now it only has 0.1 Watt output for tune no
> matter the "out" menu setting; the same for 10 Mhz.  All frequencies
> appear to be within the allowed band (didn't move the VFO knob from
> the starting mid position during this time).
>
> Left it to start typing this question, wanted to go back and look at
> exactly what the display read and all bands but 21 Mhz would now
> output okay -- 21 Mhz still just P0.1.  I went ahead and completed the
> tune-up, skipping 21 Mhz (but starting with the 21 Mhz caps for 14
> Mhz) -- wanted to try the radio out and will be using it on 40 meters
> for now.
>
> Finished the work (speaker, etc) and hooked the rig up through a tuner
> to a dipole tossed into a couple of trees and, for the first time in
> 26 years for me, made a contact (my code skills, even with some
> practice recently, are woefully rusty).  After the QSO I did some
> cleanup and rearranging (included unplugging the K1), then brought it
> back up to try for a second contact; back to no output, if I go into
> tune I get P0.1 on screen, if I try and transmit, no power out.
>
> Any insight would be appreciated; probably (hopefully) something
> simple I'm missing.  First contact was a thrill, hope to get the
> second before another 26 years go by.  :)
>  
>

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