[TenTec] Omni-D troubleshooting

[Chris Howard w0ep]

Good question!

Yes, the digital display and the audible frequency
do seem to match.

I think the display is being reliable.

Chris




On 1/12/2015 9:25 AM, Neil Martinsen-Burrell wrote:
> Do you know if the frequency drift is real or if it is only on the digital
> display? That is, if you tune in a CW signal, does the audible frequency
> change by 1-2 kHz along with that shown on the display?  Does the same
> thing happen on 80 meters when the frequency is jumping?
> 
> The reason I ask is that your frequency problems could all be explained by
> a problem with the frequency counter that runs the digital display. The
> Omni D uses a fairly stable 5-5.5 MHz local oscillator that is then mixed
> with band-specific crystals to produce the correct frequency. The displayed
> frequency is measured separately from the oscillator and I have seen
> anomalous frequency readings even though the oscillator is working
> perfectly.
> 
> If you want another connection to wiggle, the jumper connecting the VFO IN
> and VFO OUT jacks on the back of the radio can come loose and cause
> problems.
> 
> Of course, Carl N4PY knows all of this much better than me, so I might be
> way off base.
> 
> -Neil N0FN
> 
> On Mon, Jan 12, 2015 at 8:43 AM, Chris Howard w0ep <w0ep at w0ep.us> wrote:
> 
>>
>> Hi,
>>
>> A few months ago I bought an Omni-D with power supply from an e-bay seller.
>>
>> I have been using it, and I enjoy it.
>>
>> It is exhibiting a constellation of faults which I need to repair.
>>
>> I would like to run them by the group to see if there is some
>> common wisdom about them.  It may save me some time if I can target
>> my efforts.
>>
>> 1 - frequency drifting and jumping
>>      This seems to happen on both transmit and receive.  Multiple bands.
>>
>>      The amount of drift is about 1-2 kHz.  It will usually drift downward
>>      then jump up.  This happens when I am not touching any controls.
>>
>> 2 - frequency loss
>>     I have only had this happen on 80 meters.  The frequency will jump
>>     much farther and/or the display will go to 1.0000
>>
>> 3 - low output
>>     Output while transmitting will fluctuate.
>>
>> All of these problems seem to go away if I let the radio warm-up for an
>> extended period.
>>
>> My main tuning knob seems to turn easily enough, and all of the other
>> controls seem to work ok.  I don't notice any improvement or change
>> by jiggling the bandswitch knob.
>>
>> My only attempt at repair, so far, has been to remove the top and bottom
>> covers and re-seat all of the circuit boards I could find that had
>> the pin connectors.  I did that yesterday, but still experienced
>> drifting/jumping afterwards.
>>
>>
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