[Elecraft] K1 1408 passed the smoke test, but the VFO will not change frequency

Sun Dec 1 02:04:00 2002

I just checked the drawing and you are correct. I have the wires in the pc
board from the pins marked one, two three on the pot to 1, 2 and 3 on the
board. It is wrong according to the drawing. It should have pin 3 on the pot
to pin 3 on the board, pin 2 on the pot to pin 1 on the board and pin 1 on
the pot to pin 2 on the board. I have not swapped 1 and 2 yet, but they are
in wrong and I bet it will work after that!

You get the brass ring on this one, thanks!!

Jess AE0CW <><
----- Original Message -----
From: "Juerg Tschirren" <[email protected]>
To: "Jess Gypin" <[email protected]>
Cc: <[email protected]>
Sent: Saturday, November 30, 2002 23:50 PM
Subject: Re: [Elecraft] K1 1408 passed the smoke test, but the VFO will not
change frequency

>
> Sounds like to got the wires at pin 1 and pin 2 of the pot swapped. Check
> the drawing in the manual, p. 22. The labels on the pot itself are
> confusing. I had the exact same problem :-)
>
> Juerg
>
>
> --... ...--   -.. .   -. ----- .--. .--.
>
> On Sat, 30 Nov 2002, Jess Gypin wrote:
>
> > Hi all,
> >
> > I am at the point where I need to set the upper and lower frequencies of
the
> > VFO and it will not change frequency. The oscillator shows 3093 hz. The
VFO
> > will not change frequency. I have traced the 10 turn pot to P1 of RP-2
and
> > verified the xtals on the filter board. The problem appears to be that
the
> > voltage at D3 is not changing. With the change in resistance of the
tuning
> > pot, the voltage at P2 of RP-2 and at the cathode of D3 never changes
from
> > 5.91 volts unless I hit the clockwise stop and the pot resistance almost
> > goes to 0, then the VFO will jump and change frequency. Also the voltage
at
> > the cathode of D4 never goes below 2.91 but that is to be expected if
the
> > voltage at the first varacter is not changing.
> >
> > I ohmed out the varacters for D3 and D4, and they measure about 600 ohms
one
> > way and infinite the other. I would assume that since I am getting a
voltage
> > change with the pot at the stop and the frequency changing, that the VFO
> > works, but the voltage at the varacters in not changing with the change
in
> > resistance at the 10 turn pot.
> >
> > This is driving me nuts. I had hoped to have this finished in time for
my
> > trip to Boston on Monday to pass the nights in the hotel. Any clues or
> > insights would be greatly appreciated.
> >
> > Jess AE0CW <><
> >
> >
> > _______________________________________________
> > Elecraft mailing list: [email protected]
> > You must be a list member to post to the list.
> > Postings must be plain text (no HTML or attachments).
> > See: http://mailman.qth.net/mailman/listinfo/elecraft
> > Elecraft Web Page: http://www.elecraft.com
> >
>