[Elecraft] Re: s/n 4276 VCO Alignment issue

[W3FPR - Don Wilhelm]

William,

That behavior is quite common if there is a solder bridge on the thermistor
board.
Check it over very carefully and I believe you will find it.

73,
Don W3FPR

> -----Original Message-----
>
> K2 s/n 4276
>
> VCO Alignment (p61)
> VFO set at 4000 kHz
> L30 verified as a 4.7 uH "T005Z"
>
> Adjusting L30 has no effect on R30 voltage reading.
>
> *************************************************
>
> At TP3, there is a 12100.93 kHz signal present.
> At TP1, there is a 7717.86 kHz signal present.
> R30 is only 0.019v
> Visually inspected all components, verified that all are the
> correct values and no components are installed backwards. Solder
> joints look ok. No solder bridges or un-soldered connections found.
>
> Changing bands does not change the reading at R30.
>
> Visually inspected D16 and D17, both appear OK.
>
> RFC15 is 8.5 ohms
>
> U6-1 during PLL test, goes from 0.006v to 7.63v
>
> U6-5 is steady at 4.004v
>
> RFC14 leads look good and has 10 turns.
>
> RFC15, C91 and C88 reinspected and appear ok.
>
> T5 looks like the photo. Tried spreading and compressing the
> windings. No change in voltage readings at R30.
>
> Other measurements:
> U6-1 = 7.65v
> U6-5 = 4.004v
> U6-6 = 4.88v
> U6-7 = 0.019v
> U6-8 = 8.05v
>
> U4-16 = 4.88v
>
> Please advise.
>
> Thank You
> William Smith
> KC4WVL
>