[TenTec] OMNI C Mixer or PTO problem

Rick - DJ0IP / NJ0IP Rick at DJ0IP.de
Mon Feb 20 14:28:11 PST 2012 

Mike,

I only have a manual for the older Omni A/D.
Assuming it is the same, then:

The Accessory socket has two VFO related connections, Pin 4 and Pin 5.

Pin 4 is "REM VFO".  I could not find a description, but I think I know what
it is for.  The Omni has the LO frequency shifted by 10 kHz on two bands to
avoid birdies.  To compensate for this shift, a varactor diode is activated
in the PTO to shift it by 10 kHz in the opposite direction.  The Pin 4
signal is the switched voltage to activate to varactor in the external VFO
when you are on 10 or 15m.  Therefore there is NO ACTION necessary for this
pin.

Pin 5 is connected into the cable which runs from the VFO AMP board's "OUT"
signal line, to the LO input of the TX Mixer board.  The only use I could
see for this would be if you have the OMNI A and an external VFO with
digital readout, perhaps the PTO signal was tapped into here to feed the
digital frequency display in the external VFO.  

There is NO association of Pin 4 with Pin 5.  It would be disastrous to
connect a jumper across the two pins.
No other pins have anything to do with the VFO or LO.  

***THEREFORE, THERE IS NO JUMPER ON THE ACCESSORY BOARD.***

Assuming of course it is the same on the Omni C, as on the Omni A and D.

I will see if I can download an Omni C manual and join in the search with
you guys.

73
Rick, DJ0IP 

-----Original Message-----
From: tentec-bounces at contesting.com [mailto:tentec-bounces at contesting.com]
On Behalf Of Michael Silevitch
Sent: Monday, February 20, 2012 10:51 PM
To: Discussion of Ten-Tec Equipment
Cc: Michael Silevitch
Subject: Re: [TenTec] OMNI C Mixer or PTO problem

Dear Joe

Yes, there is an accessories socket but there is no mention in the manual
of a jumper that needs to be in place between pins on the socket for the
Omni. There is a mention of this need in the Corsair manual. (Sorry for
the confusion)

Regards
         Mike


On 2/20/12 4:43 PM, "Joe" <joe at n4yg.com> wrote:

>Mike,
>
>Are you sure there is no ACCESSORIES jack on the rear panel. It is a
>9-pin 
>Molex connector. If it is not there, then you are right, there will be no
>jumper. The manual for the OMNI A clearly has this jack. I do not
>understand 
>why an upgrade would not also have it.
>
>Joe
>----- Original Message -----
>From: "Michael Silevitch" <msilevitch at coe.neu.edu>
>To: "Discussion of Ten-Tec Equipment" <tentec at contesting.com>
>Sent: Monday, February 20, 2012 3:36 PM
>Subject: Re: [TenTec] OMNI C Mixer or PTO problem
>
>
>> Dear Joe
>>
>> I hope you and Gary are right. I'll give Ten Tec a call on this
>>tomorrow. 
>> As I said to Gary there is no reference to the accessories jumper in
>>the 
>> Omni C manual. There are at least two references to it in the Corsair
>> manual.
>>
>> Regards
>>   Mike
>>
>> Sent from my iPhone
>>
>> On Feb 20, 2012, at 4:27 PM, "Joe" <joe at n4yg.com> wrote:
>>
>>> Did you see the post by Gary, AB9M. I still think there is an
>>>accessory 
>>> jack
>>> and that a jumper is required.
>>> ----- Original Message -----
>>> From: "Michael Silevitch" <msilevitch at coe.neu.edu>
>>> To: "Discussion of Ten-Tec Equipment" <tentec at contesting.com>
>>> Cc: "Michael Silevitch" <msilevitch at coe.neu.edu>
>>> Sent: Monday, February 20, 2012 2:46 PM
>>> Subject: Re: [TenTec] OMNI C Mixer or PTO problem
>>>
>>>
>>>> Dear Joe
>>>>
>>>> I'll look into the external VFO question. I have the manuals for both
>>>> the
>>>> 243 and the 263 so that should tell me something. Also I son't see
>>>>that
>>>> there is a jumper needed on the accessories socket like the Corsair
>>>>has. 
>>>> I
>>>> could be wrong about this but that's what is seems to be.
>>>>
>>>> Regards
>>>>        Mike
>>>>
>>>>
>>>>
>>>> On 2/20/12 1:35 PM, "Joe" <joe at n4yg.com> wrote:
>>>>
>>>>> Well Mike, I guess the next thing to do is to see if there is
>>>>>anything
>>>>> coming out of the PTO. You could use one of the scopes that everyone
>>>>> has
>>>>> been talking about or an RF probe. It is looking like the PTO may
>>>>>have 
>>>>> no
>>>>> output. You can check that at the VFO OUT jack on the rear. That
>>>>>brings
>>>>> up
>>>>> an interesting question. If there is no way to turn the PTO off, how
>>>>>do
>>>>> they
>>>>> handle remote VFOs?
>>>>>
>>>>> ----- Original Message -----
>>>>> From: "Michael Silevitch" <msilevitch at coe.neu.edu>
>>>>> To: "Discussion of Ten-Tec Equipment" <tentec at contesting.com>
>>>>> Cc: "Michael Silevitch" <msilevitch at coe.neu.edu>
>>>>> Sent: Monday, February 20, 2012 11:45 AM
>>>>> Subject: Re: [TenTec] OMNI C Mixer or PTO problem
>>>>>
>>>>>
>>>>>> Dear Joe
>>>>>>
>>>>>> That's unfortunately right. The OMNI PTO circuitry does not have an
>>>>>> Enable
>>>>>> line. The Corsair does.
>>>>>>
>>>>>> Any other wisdom?
>>>>>>
>>>>>> Regards
>>>>>>        Mike K1PEV
>>>>>>
>>>>>> ****************************************
>>>>>>
>>>>>>
>>>>>>
>>>>>> On 2/20/12 9:22 AM, "Joe" <joe at n4yg.com> wrote:
>>>>>>
>>>>>>> I guess I made have assumed too much Mike. I thought all the later
>>>>>>> PTOs
>>>>>>> had
>>>>>>> an E terminial which allowed the PTO to be rapidly switched on and
>>>>>>> off
>>>>>>> when
>>>>>>> a remote VFO is used. If the OMNI does not have an accessory jack,
>>>>>>> then
>>>>>>> you
>>>>>>> can probably disregard  all of what I said.
>>>>>>>
>>>>>>> Joe
>>>>>>> ----- Original Message -----
>>>>>>> From: "Michael Silevitch" <msilevitch at coe.neu.edu>
>>>>>>> To: "Discussion of Ten-Tec Equipment" <tentec at contesting.com>
>>>>>>> Cc: "Michael Silevitch" <msilevitch at coe.neu.edu>
>>>>>>> Sent: Monday, February 20, 2012 8:06 AM
>>>>>>> Subject: Re: [TenTec] OMNI C Mixer or PTO problem
>>>>>>>
>>>>>>>
>>>>>>>> Dear Joe
>>>>>>>>
>>>>>>>> This sounds encouraging but can you give me a bit more detail? The
>>>>>>>> OMNI
>>>>>>>> schematic doesn't indicate an E reference. The PTO block only has
>>>>>>>>a
>>>>>>>> few
>>>>>>>> outputs (VFO out, VFO shift and OT). None of these are linked to
>>>>>>>>the
>>>>>>>> accessories socket. Also the manual doesn't mention that a jumper
>>>>>>>>is
>>>>>>>> needed on the accessories socket. The Corsair does have a jumper
>>>>>>>> installed
>>>>>>>> when not using an external VFO. What pins on the socket need to be
>>>>>>>> jumped?
>>>>>>>>
>>>>>>>> Regards
>>>>>>>>        Mike K1PEV
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> On 2/20/12 8:38 AM, "Joe" <joe at n4yg.com> wrote:
>>>>>>>>
>>>>>>>>> Check the E voltage at the PTO. If this voltage is not about 8
>>>>>>>>> volts,
>>>>>>>>> the
>>>>>>>>> PTO is disabled. The E voltage is jumpered at the ACCESSORY jack
>>>>>>>>>on
>>>>>>>>> the
>>>>>>>>> rear
>>>>>>>>> panel. If it is not jumpered, the PTO will not have the E
>>>>>>>>>(Enable)
>>>>>>>>> present
>>>>>>>>> will thus be disabled.
>>>>>>>>> ----- Original Message -----
>>>>>>>>> From: "Michael Silevitch" <msilevitch at coe.neu.edu>
>>>>>>>>> To: <tentec at contesting.com>
>>>>>>>>> Cc: "Michael Silevitch" <msilevitch at coe.neu.edu>
>>>>>>>>> Sent: Monday, February 20, 2012 7:18 AM
>>>>>>>>> Subject: [TenTec] OMNI C Mixer or PTO problem
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> I am trying to understand a problem with my newly purchased
>>>>>>>>>>OMNI 
>>>>>>>>>> C.
>>>>>>>>>> It
>>>>>>>>>> was
>>>>>>>>>> operating fine according to the person who sold it to me (and I
>>>>>>>>>> believe
>>>>>>>>>> him!). Upon arrival it seems that the PTO has no output or
>>>>>>>>>>there 
>>>>>>>>>> is
>>>>>>>>>> a
>>>>>>>>>> problem mixing the PTO signal. The reason I say this is because
>>>>>>>>>>I 
>>>>>>>>>> am
>>>>>>>>>> observing displays of 9MHz, 1 MHz or 91MHz depending on the
>>>>>>>>>>band.
>>>>>>>>>> There
>>>>>>>>>> is
>>>>>>>>>> no transmitter drive current. According to the manual the
>>>>>>>>>>display
>>>>>>>>>> output
>>>>>>>>>> is
>>>>>>>>>> a sign that mixing with the PTO is not occurring. I assume this
>>>>>>>>>> also
>>>>>>>>>> correlates with no transmitter current. I think (hope) the
>>>>>>>>>>problem
>>>>>>>>>> is
>>>>>>>>>> something simple that was caused by the rough and tumble of
>>>>>>>>>> shipping.
>>>>>>>>>> I
>>>>>>>>>> did
>>>>>>>>>> try things like testing the VFO out-in jumper, jiggling cables,
>>>>>>>>>> leaving
>>>>>>>>>> the
>>>>>>>>>> unit on overnight, etc. I do have the option of shipping the
>>>>>>>>>>unit
>>>>>>>>>> back
>>>>>>>>>> but
>>>>>>>>>> I
>>>>>>>>>> would rather fix it if it is a simple fix.
>>>>>>>>>>
>>>>>>>>>> Another question. Will the Corsair 263 VFO work on the OMNI C?
>>>>>>>>>>
>>>>>>>>>> I would greatly appreciate any advice on this problem.
>>>>>>>>>> Regards
>>>>>>>>>>
>>>>>>>>>>        Mike K1PEV
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> _______________________________________________
>>>>>>>>>> TenTec mailing list
>>>>>>>>>> TenTec at contesting.com
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>>>>>>>>>
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