John,
At some point I'll borrow a signal generator and set it up right. But it
works OK for now.
Thanks.
Frank
KK4PR
On Sun, Sep 19, 2010 at 1:09 AM, John Callari <john@callari.us> wrote:
> Frank:
>
> I never made the adjustment because I didn't have a signal generator... I
> wasn't going to
> fiddle with the R45 without having a true sense for what the actual signal
> strength was...
> Plus, the Omni V was not going to be put back into service here, so I
> figured I'd leave it
> to the person who bought it to adjust it to their standards... :)
>
> Glad the Omni is safe and working well!
>
> John
> K2JNC
>
> On Sep 18, 2010, at 7:28 AM, Frank Kirschner wrote:
>
> > Well, I assumed that if it were that simple, someone else would have made
> > the adjustment. (Note to self: Don't assume.)
> >
> > You're absolutely right: all it took was adjustment. R45 was set at its
> > highest sensitivity. There is also an S-meter offset adjustment. I set
> the
> > S-meter to read between 0 and 1 on ten meters with no antenna connected,
> and
> > to read around S-9 or a little above for a local 80 meter signal. It may
> > not be perfectly accurate, but it gives a good relative indication, and I
> no
> > longer worry about bending the needle.
> >
> > Thanks.
> >
> > 73,
> > Frank
> > KK4PR
> >
> > On Sat, Sep 18, 2010 at 1:31 AM, Dr. Gerald N. Johnson
> > <geraldj@weather.net>wrote:
> >
> >> As far as I know the manual with circuit diagrams that you can download
> >> from Tentec is all the "service" manual there is. Looking at it I have
> >> found that there is an S-meter sensitivity adjustment R45 on the IF/AF
> >> board along with an S-meter offset R43. It looks like R43 sets the zero
> >> and R45 sets sensitivity from low to very high. I don't know the value,
> >> but there is no fixed resistor to limit hypersensitivity. Providing the
> >> AGC is enabled, you should be able to adjust R45 to any sensitivity you
> >> like, providing the pot hasn't gone bad with age. If the pot has an open
> >> resistive element it may only work set up way too high. The pot may have
> >> an identification resistance on it to allow finding a generic
> >> replacement or to allow a will guess for value, at about 1/2 the pot's
> >> total resistance to be put in as a fixed resistor.
> >>
> >> The other thing that can cause an S-meter to be hypersensitive is leaky
> >> bypasses on the AGC line so that AGC control is poor, e.g. that it takes
> >> a large AGC voltage to reduce the RF and IF gain. Maybe the RF gain
> >> controlled stage is on another board and the cable between them is open.
> >> It might be two common Tentec service procedures are in order. One is to
> >> tighten all the board mounting screws to make sure the grounds are good.
> >> The other is to apply a quarter drop of DeoxIT to each cable connector
> >> pin and slide the connector off and on a few times to get a solid
> >> connection again.
> >>
> >> If all that's needed is setting R45, you will have to judge by ear what
> >> signals are strong and weak, like we did before we could run AGC on a
> >> receiver on CW or SSB, and adjust the meter for a satisfying reading
> >> that matches your perception by ear.
> >>
> >> If R45 proves to be open, Cramolin who makes DeoxIT makes a pot restorer
> >> product that might work.
> >>
> >> 73, Jerry, K0CQ
> >>
> >> On 9/17/2010 7:54 PM, Frank Kirschner wrote:
> >>> I just bought an Omni V with the N4PY mod. It works great, except for
> >> the S
> >>> meter. I was told when I bought it that it was hypersensitive, and
> that
> >> is
> >>> true.
> >>>
> >>> Is there a "most frequent" cause for this? I sold or gave away all my
> >> test
> >>> equipment years back, so can't do much exploration at this point. I'd
> >>> appreciate ideas. I have the regular operation manual, but no service
> >>> manual.
> >>>
> >>> Also, the knobs are a little greasy. Is there a mild solvent people
> have
> >>> used to clean the knobs without removing the paint?
> >>>
> >>> Thanks.
> >>>
> >>> 73,
> >>> Frank
> >>> KK4PR
> >>>
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> >> TenTec@contesting.com
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> >>
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>
>
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