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
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>>>
>>
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