[TenTec] Omni VI+ S meter troubleshooting

[Phil Erickson]

Hi John,

   Good suggestion - I'll try measuring the coil resistance.  I think I
might also set up a potentiometer and a battery and try feeding some
current in to check needle deflection.  (The meter doesn't seem to have a
full scale marking, alas, and Ten-Tec didn't label that on its circuit.)
 Will let you know how it turns out.

73
Phil W1PJE

On Sat, Nov 17, 2018 at 2:42 AM John Hodge <john at hodge.uk.com> wrote:

> I have an Omni VI+. You could put an analogue test meter across the S
> meter coil. This would do 2 things: check the meter coil resistance and
> cause the needle to deflect.
>
> John G8CCD
>
> ⁣Sent from TypeApp
> on Lenovo Yoga Tab 3​
>
> On 17 Nov 2018, 04:41, at 04:41, Phil Erickson <phil.erickson at gmail.com>
> wrote:
> >Hi all,
> >
> >I've just acquired an Omni VI+ with all the filters including the Inrad
> >roofing filters.  It is very sensitive as far as RF goes on all bands
> >using
> >a HP 8640B signal generator as a calibrated source.  However, the S
> >meter
> >does not work at all when AGC is enabled (or for that matter, when it
> >isn't, although of course AGC should be on to generate a reading).
> >
> >I pulled the covers off and examined the IF/AF board.  According to the
> >manual section 4-7, the voltage driving the S meter is at connector 58
> >(a 2
> >pin one).  I pulled the connector off and, using a multimeter, was able
> >to
> >verify that a correct voltage was there on the pins in the ~200 to 800
> >mV
> >range.  I was able to make that voltage go up and down as expected by
> >manipulating  the RF gain, and also by changing the signal generator's
> >amplitude.  The R25 and R29 trimmers also made the voltage move up and
> >down
> >as expected ("full scale" and "offset').
> >
> >So I think the S meter driving circuitry is working fine in RX mode
> >from
> >the IF/AF board..
> >
> >However, the manual is not clear on how the meter is multiplexed with
> >the
> >TX section, which I haven't tried yet as I'd like to get the receiver
> >going
> >first.  I tried moving the meter selector knob to a few positions, but
> >of
> >course all of those are for when the TX is engaged (FWD, SWR, Ic, PROC)
> >so
> >it did not help.
> >
> >  Does anyone have suggestions?
> >
> >1)  Maybe the meter movement has failed?  If so, does anyone have any
> >tips
> >to isolate the meter and drive it with an appropriate voltage to see if
> >the
> >needle moves?
> >
> > 2)  Is there any other check to see if the meter is somehow not paying
> >attention on RX because it's stuck on one of the TX meter settings?
> >
> >  3) Are there any other connectors to reseat?
> >
> >Thanks in advance -
> >
> >73
> >Phil W1PJE
> >
> >
> >
> >
> >--
> >----
> >Phil Erickson
> >phil.erickson at gmail.com
> >_______________________________________________
> >TenTec mailing list
> >TenTec at contesting.com
> >http://lists.contesting.com/mailman/listinfo/tentec
> _______________________________________________
> TenTec mailing list
> TenTec at contesting.com
> http://lists.contesting.com/mailman/listinfo/tentec
>


-- 
----
Phil Erickson
phil.erickson at gmail.com