[TenTec] Omni VI+ S meter troubleshooting

Phil Erickson phil.erickson at gmail.com
Fri Nov 16 23:55:34 EST 2018

Haven't tried TX mode yet because I didn't have a dummy load when I was
doing testing.  I was hoping there was a quick way to test the meter
without that.

Phil W1PJE

On Fri, Nov 16, 2018 at 11:41 PM Phil Erickson <phil.erickson at gmail.com>

> 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

Phil Erickson
phil.erickson at gmail.com

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