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K2 VCO Alignment T5 L30

Posted by K2bew on Jan 18, 2019; 1:48pm
URL: http://elecraft.85.s1.nabble.com/K2-VCO-Alignment-T5-L30-tp7648249.html

Don et al,

Since I know Don monitors the reflector as well as the support emails,
rather than email Don directly I thought I would ask the question on here
because I know I always find it helpful to read other peoples questions on
here and Don's answer.

Building the K2 I am at the VCO Alignment voltage check on R30 and
adjusting L30.
VFO frequency set at 4000.00 kHz
I initially got 3.5 volts and bottomed out L30 to get it to 5.5 volts, and
then I over screwed it to try to get that last half a volt and ended
damaging it, so, then I carefully took out L30 and put in a new one.

I also took out T5 and rechecked all the ends for continuity, rewound the
green wire to space it exactly in the middle of the red winding and spaced
everything evenly. I confirmed it is the large yellow core, I have 16 on
the red wire and 4 on the green (by the way the illustration shows 14 turns
of red) . I verified I have R30 as Br-R-Br 120 ohms with both my DVM and by
color, and I verified C72 is 271, and I reflowed the solder on both.
With a new 4.7 inductor (large slot, no red mark) in L30 I now get 2.75
volts on the left side of R30 to start with and it bottoms out at 4.5 volts
(I was very careful to not bottom it out too hard this time and damage this
one, and I have already ordered a couple new ones from Elecraft).

What else can I do to increase that voltage? Would changing the number of
windings on T5 change it enough to get to 6 volts?

Thank you and 73,
Tom Bewick K2BEW
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