Joseph,
Blame it on poor lighting at the computer (and my eyes) - yes, C60 is
the appropriate capacitor.
So the VFO ALC is not the problem - you will have to discover why the
VFO is not oscillating. It could be a problem with Q18 or anything in
its circuit. Do check Q18 for the correct FET type (J310) and the
orientation of D13 and D8 - refer to the parts placement diagram in the
back of the manual for the diode orientation.
73,
Don W3FPR
On 4/29/2014 10:51 PM, Joseph Baxley via Elecraft wrote:
Don,
Thanks again. I had one question from your last email. Did you mean C60? I
couldn't find C50 in the VFO circuit. I shorted C60 which put the drain to
ground. Still no help. The BFO is working though, so that's good news. I
also checked D13 and D8. They match the outline on the board, so they should
be good. I will try again tomorrow when I've had some rest. Sometimes I've
found fresh eyes help me see things I missed the night before.
Joseph
On Tuesday, April 29, 2014 9:15 PM, Don Wilhelm-4 [via Elecraft]
<ml-node+s365791n7588159...@n2.nabble.com> wrote:
Joseph,
See if the VFO is oscillating. Check the internal counter probe by
plugging it into TP2 and use menu CAL FCTR - you should see a frequency
near 4913 kHz (the BFO frequency). If that is good, the counter probe
should be working. Then plug the probe into TP1. The frequency should
be near the K2 dial frequency plus 4913 kHz. If you see that frequency,
all is OK with the VFO.
If you instead see all zeros, the VFO is not oscillating, and you will
have to figure out why.
You have already checked the winding of T5, so there may be something
else. Check the orientation of D13 and D8 as starters. Then eliminate
the VFO ALC from the picture by placing a short from the drsin og Q17 to
ground (a convenient place to do that is to put a temporary solder
bridge across the leads of C50). Do you get a VFO frequency reading
with that in place? If so check the soldering of the VFO ALC
components. Look on the schematic and find on sheet 1 for the RF Board
all the components in the area labeled VFO ALC and check the soldering
of all those components - remove the solder bridge from C50 and see if
it still oscillates. If it does, you should be on your way to success.
73,
Don W3FPR
On 4/29/2014 9:13 PM, Joseph Baxley via Elecraft wrote:
Don, Matt,
I looked at the transformer and have double checked him. I saw that there
was electrical continuity between leads 1 & 2 and 3 & 4 (i.e. zero Ohm
resistance between said leads). Also, 3 & 4 are the green leads. I checked
that the green wires weren't crossing and that they were spaced each turn
between the red wires. I did notice that they weren't exactly centered,
with more red turns before lead three than after lead four. I pulled the
transformer out and rewound the green wires to center them and see if it
helped any. No dice. Also I checked the number of turns, 16 red and 4
green. I'm intimately familiar with not having properly stripped the wires.
That was a problem building my K1!
I'm fairly certain then that the transformer is not the problem. I've been
checking things like the diodes that run through the VCO to make sure that I
have not put in one backwards. I've also been looking for cold joints or
solder bridges. Haven't found one yet.
Thanks,
Joseph
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