Yes, you did good. One thing I learned when a friend had a project go south
and could not find the reason. He brought it to me and it was an enameled wire
that he had not striped the enamel off. The connection looked good but it did
not burn through the enamel. Again DETAIL and double checks. Now where did I
put my keys,,,,,,,
Mel, K6KBE
From: Ron D'Eau Claire <r...@cobi.biz>
To: 'Cameron Francey' <cameronfranceyut...@hotmail.com>;
elecraft@mailman.qth.net
Sent: Saturday, February 25, 2017 3:41 PM
Subject: Re: [Elecraft] Elecraft K2/10 Build and a lesson learned.
Glad it turned out well in the end, Cameron. All "solder jockeys" know how a
joint sometimes magically "desolders" itself.
You were lucky after all. Often the unsoldered joint is making contact with
the thru-plated hole and everything works - until a little oxide builds up
and the resistance climbs until the circuit is open - often months or even
years later. Of course by then a component failure is the prime suspect and
many hours can be lost looking everywhere but the solder joints.
Enjoy your new K2. I built mine in 2000 and it is still a FB rig.
73, Ron AC7AC
-----Original Message-----
From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of
Cameron Francey
Sent: Saturday, February 25, 2017 3:03 PM
To: elecraft@mailman.qth.net
Subject: [Elecraft] Elecraft K2/10 Build and a lesson learned.
Hi All,
I Just finished my Elecraft K2/10 build. I have lots of options to add but
the basic K2/10 is now working and I'll let it settle in for a week or so to
make sure its all ok before adding any options.
I started this build at the end of January, taking care to sort and identify
all the parts, especially the fixed value capacitors so it made life much
easier to select the correct values efficiently during the build.
Everything went well, got the phase 1 and 2 tests done, added the remainder
of the components to finish phase 3 and then when I got to the transmitter
alignment step I noticed that rather than about 2 watts out as expected it
was over 20 watts! Gee, what was wrong I thought to myself? I had a quick
look over everything, made 100% sure all the components were installed
correctly etc, but couldn't find anything wrong. I even re-counted all the
transformer winding's and made sure they were all installed correctly.
Nothing looked out of place.
Having recently built two K1's and a K2/100 with KAT100 and nearly every
option available I knew it had to be something I had done wrong. So I kept
my logic head on and decided after my initial disappointment and re-checking
my work that a break away from the bench was a good start.
Back to the bench this morning with a fresh mind I suspected that my issue
was somehow with the components that either set or control the power level,
and my reason for thinking that was because the issue was present on every
band and the power control pot made no difference to the output power, and
RX wise it was performing really well so that eliminated a lot of the
sections. Thinking about ALC or the power control circuit on the control
board I decided that was where to start and work outwards from there. I
knew the transmit section of the main RF board was in good shape since it
was capable of producing more than 20 watts into a dummy load!
So, I read the circuit diagram, pulled out the control board and started to
trace the ALC circuit though the board.. That's when I found my problem, I
couldn't believe how stupid I had been and missed soldering pin 2 of RP 3 on
the Control Board, which is the ALC feedback loop. After soldering that and
re-testing all was well, phew!!!
Where the lesson was learned was even though I'm close to obsessive
compulsive when identifying and selecting each component and double checking
twice before soldering anything, then checking with a magnifying glass that
the joints look good I still somehow managed to let that un-soldered pin go
unnoticed!
I don't think I have caused any adverse effects to the PA section driving it
so hard. The short periods of transmitting at about 23 watts never caused
them to heat up. Its interesting that the PA produced over 20 watts, so the
15 watts max output under normal conditions seems quite a conservative level
for those 2SC1969's.
Just thought I'd share my stupid mistake with the readers here and that even
being really careful things can still slip through the net!
Best Regards,
Cameron, AF7DK/GM7LQR
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