[TenTec] OMNI C Mixer or PTO problem

Mon Feb 20 13:56:59 PST 2012

There are definitely  VFO in/VFO out jacks on the backplane, and a jumper to 
connect the two of them together is required.

Elsewise, the VFO output is not connected to the mixer, and the counter will 
read 9 mHz.

I would not be adjusting anything to cure this problem.  If you don't have a 
missing jumper, you most likely have a loose connection, and when you find 
it, you don't want to have anything out of adjustment that might hide the 
result.

I've repaired several Corsairs with this symptom, and they have usually had 
a problem on the mixer board.  There's a connector there for the PTO signal, 
and the staking pins, for some reason, are very easy to break loose from the 
foil.

Phil C. Sr.
k4dpk
----- Original Message ----- 
From: "Joe" <joe at n4yg.com>
To: "Discussion of Ten-Tec Equipment" <tentec at contesting.com>
Sent: Monday, February 20, 2012 4:43 PM
Subject: Re: [TenTec] OMNI C Mixer or PTO problem

> 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
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> _______________________________________________
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