OK, I am involved in three threads regarding Paragons, Omni 5’s and Omni 6’s so
I have gotten some crosstalk…
If you select a filter position on your radio that has no filter in it, do you
still hear the clicking sound when tuning?
Gary
> On Sep 29, 2018, at 5:33 PM, Byron Cordes via TenTec <tentec@contesting.com>
> wrote:
>
> The radio is a Omni VI. Radio does rx and tx . can here and talk to people
> even on 20 meters where that vfo noise is . Higher noise floor on 40- 160 you
> don’t here the vfo noise but on 20 meters it is very loud higher than the
> people talking when tuning . Stop turning vfo and radio sounds normal with
> people talking .
>
> Sent from my iPad
>
>> On Sep 29, 2018, at 5:23 PM, MadScientist <dukeshifi@comcast.net> wrote:
>>
>> Sorry, I misread… I was focussed on a previous radio (a Paragon).
>>
>> Your problem is most certainly due to the fact that the 5.0 to 5.5 MHz PLL
>> is going out of lock. This model does not produce any out-of-lock fault
>> regardless of the lock condition of the PLL so it can be out-of-lock with no
>> indication of that condition. The radio will still produce normal band hiss
>> but you will not be able to tune in signals.
>>
>> Oddly, he radio will still transmit in this condition, but well out of the
>> Ham bands! It will transmit on the frequency at which the VCO settles when
>> out-of lock, about 14.6 MHz, regardless of dial setting or display readout
>> reading. It will also be very unstable.
>>
>> From what you describe (now that I am on the right page model-wise) i would
>> suggest replacing the dual gate MOSFET in the loop IF.
>>
>> I recently repaired an Omni 6 that had the same problem as your Omni 5 has.
>> That FET was the culprit and what’s worse, it pulled the alignment due to
>> leakage of the device. It was highly intermittent. The heat/cool method was
>> the only way I could point to it, but monitoring the loop test point was the
>> only way I could prove it to myself.
>>
>> The way to really determine if this is the fault is to put a voltmeter on
>> the 10K resistor test point of the loop IF (That resistor stands up on the
>> board whereas all of the others lie down, and the test point is the high end
>> of that resistor (thankfully). Then, from a cold start of the radio, monitor
>> that voltage as the warmup progresses. While the PLL will lock with as
>> little as 80 mV at t his point, it will be unstable. You SHOULD get, as I
>> said, >300 mV at all three band test frequencies.
>>
>> The actually band selection is not important because this PLL operates the
>> same regardless of band. However, an exception exists in that the PLL will
>> not tune to “500” position on 40 meters.
>>
>> Also, the PLL tunes in opposite directions on low bands and high bands. That
>> is why I chose 20 meters to select which coil to peak at what frequency.
>>
>> I used a BF988, available from Littediode on eBay to replace the loop IF
>> FET. The devices I get for Littlediode always work so they are a safe seller
>> IMHO.
>>
>> You may need to align the loop IF if you do not get at least 300 mV DC on
>> the loop IF test point on all portions of the band (14.000, 14.250 and
>> 14.500) since this is a broadly tuned LC IF stage that was likely originally
>> aligned using a sweep generator.
>>
>> I approximated the sweep generator by aligning the three IF coils, one a
>> tach frequency test point. The left most I peaked at 14.200, the middle one
>> at 14.250 and the right most one at 14.500 (radio on 20 meters, of course).
>>
>> Gary
>>
>>> On Sep 29, 2018, at 3:42 PM, Dry Martini Holding Company😎 <qrp@kg4kgl.net>
>>> wrote:
>>>
>>> I have a similar issue with my V.9. When I first turn it on, it will be
>>> fine then recv audio will drop out. If I leave it on for 15 or 20 min, recv
>>> audio becomes normal again and is fine the rest of the day.
>>> st point
>>> I sent mine to steve Yudell in Florida and he had it for a couple of weeks
>>> and it worked fine for him after he went through it. Now that I have it
>>> back it has started doing it again. I just don’t feel like boxing it up and
>>> sending it back. I am just going to live with it.
>>>
>>> If you find out what the problem is, let me know.
>>>
>>> Robert
>>> KG4KGL
>>>
>>>> On Sep 29, 2018, at 15:40, arsn4dd@charter.net wrote:
>>>>
>>>> Is there an Omni V mechanic in the house? My radio is going to need
>>>> one if it doesn't straighten up... HI HI
>>>> I have a very sparingly-used Omni V.9 that has developed an
>>>> intermittent receive issue. From a cold start, the radio powers up and
>>>> operates properly. After some random period of time, I can power cycle
>>>> the radio, and as a result, I lose receive signals. I retain plenty of
>>>> audio, and plenty of what sounds like band noise, but there no signals
>>>> anywhere. I can leave the radio off for a couple of minutes, power it
>>>> up, and the signals return. Before the suggestion is floated, I have
>>>> exercised every connection in the radio with DeOxit. I have tightened
>>>> and re-tightened every screw on every board in the radio. I have not,
>>>> however re-seated any of the chips. Is there enough information here
>>>> to generate suggestions? I admit to being mostly an appliance
>>>> operator, but I might be capable of doing a few diagnostics. Thanks in
>>>> advance for any guidance.
>>>> Best Regards to all!
>>>> Dennis N4DD
>>>> _______________________________________________
>>>> TenTec mailing list
>>>> TenTec@contesting.com
>>>> http://lists.contesting.com/mailman/listinfo/tentec
>>>>
>>>
>>> _______________________________________________
>>> TenTec mailing list
>>> TenTec@contesting.com
>>> http://lists.contesting.com/mailman/listinfo/tentec
>>
>> _______________________________________________
>> TenTec mailing list
>> TenTec@contesting.com
>> http://lists.contesting.com/mailman/listinfo/tentec
> _______________________________________________
> TenTec mailing list
> TenTec@contesting.com
> http://lists.contesting.com/mailman/listinfo/tentec
_______________________________________________
TenTec mailing list
TenTec@contesting.com
http://lists.contesting.com/mailman/listinfo/tentec
|