[TenTec] Omni VI+ S meter troubleshooting
dukeshifi at comcast.net
Fri Nov 16 23:43:42 EST 2018
Does the meter read in transmit?
> On Nov 16, 2018, at 10:41 PM, 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 -
> Phil W1PJE
> Phil Erickson
> phil.erickson at gmail.com
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> TenTec at contesting.com
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