[Elecraft] TP2

[Peter]

>

Don and all

I did carefully removed L33 and both crystals. Replace L33 but with room to solder both
crystals on the solder side. When solder 1 crystal at the time they both give the wanted
reading and they are stable. But when both are solderd its jumping around.

>
>
> My guess is that there is a bad solder connection somewhere in the BFO area.
> The fact that things stabilize when you touch something in the area strongly
> suggests something wrong with the soldering.
>
> Pressing BAND+, BAND- when in CAL FCTR should swing the voltage between 0
> and 8 volts, so it seems things are likely OK with the control voltage.
>
> The only other thing I can think of which would cause similar behavior is a
> weak crystal.  If you suspect the crystals, try removing one of them and see
> if the behavior stabilizes (the BFO range will become more narrow - so that
> is only for a test, not a cure).  2 parallel crystals are used to 'de-Q' the
> crystals and provide a greater BFO range than one alone would provide.
>
> 73,
> Don W3FPR
>
> ----- Original Message -----
>
> > Some ask for more info.
> >
> > With the probe in TP2 and CALL on FCTR the reading jumps fast around 4.620
> > mc
> > Then the voltage on RP6 is stable reading 6,48V
> >
> > Pressing BAND -
> > The readout is 4,917 mc and stable but the voltage on RP6 has jumped to
> > 8,0V
> >
> >>
> >> I have a K2 rig here for repair and this baby has a instable frequentie
> >> reading on TP2
> >> After touching a part of the bfo its solid (4,917 mc)
> >> Q24 is working good, but on  U11 (bfo) pin 6 and 7 are 1 volt too low.
> >> I a have all ready replace D37 and D38 bun no effect.
> >>
> >> Question. Why are there 2 cristals? (X3 and X4)
> >> The low voltage on  pin6 and 7 of U11 is this caused by a defect IC or
> >> something else?
> >>
> >> Peter
> >> PC2A
> >>
> >
> >
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