[TenTec] Omni VI+ S meter troubleshooting

[Phil Erickson]

Hi Jim,

  Thanks - already checked that part out with the S meter unplugged.  I
could adjust R25 through its full range and see the voltage on a DMM go up
and down, so the pot wasn't at a dead spot, but I could certainly see where
this might happen in other cases.

73
Phil W1PJE

On Sat, Nov 17, 2018 at 12:51 AM <w3ka at lycos.com> wrote:

> Phil OM,
>
>   I had similar issues with my TT Omni 6+.  S meter readings were there
> but extremely low.
>
> On the IF/AF board, there is an S meter adjust pot, R25 a 1K trimmer
> control.  Mine was
>
> sitting on a "dead spot".  Gently rock the pot up and down, (not too much,
> just enough to free the dead spot on
>
> the trimmer).. World great on  my VI+ and resolved the S meter issues.
> Good luck
>
>
>                         73,  Jim W3KA
>
>
>
> On 2018-11-17 04:41, Phil Erickson 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