http://elecraft.85.s1.nabble.com/K2-VCO-Alignment-T5-L30-tp7648249p7648259.html
> Tom,
>
> Normally I would say to spread or compress the turns on T5, but Elecraft
> encountered a batch of J310 FETs that do not work very well at Q19 - the
> PLL reference oscillator. These troublesome FETs have now been purged
> from the Elecraft stock, that the problem should go away going forward.
> I am not sure that is your problem, but it is worthy of checking.
>
> First question is - did you get good frequency readings for the PLL
> Reference Oscillator range? If it fails, you see a strange frequency
> reading at the high frequency end (when BAND+ is tapped).
> Now, the other "funny" thing is that it sometimes checks OK with the
> internal counter probe plugged into TP3, but fails when the probe is
> removed.
>
> Under those conditions, the PLL and VFO do not lock together
>
> So the first thing to try is to solder a 10 to 15pF capacitor between
> the source of Q19 and ground. Then between a combination of adjusting
> the red turns on T5 and L30 see if you can obtain the correct R30 voltage.
>
> If that is successful, then all should be well.
>
> If not successful, get a replacement Q19 from Elecraft. Send the part
> number and description to
[hidden email] and ask for a replacement.
>
> If that does not correct things, then email me and we can go through
> some other checks to determine the source of the failure.
>
> 73,
> Don W3FPR
>
> On 1/18/2019 8:48 AM, K2bew wrote:
> > 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
>