[TenTec] OMNI C Mixer or PTO problem

[GARY HUBER]

Its been at least twenty years since I sold my OMNI-C and replaced it with 
the CORSAIR-II still on my operating desk. Both radios were ordered with 
external VFOs but were occasionally run with out and required both a jumper 
in the VFO IN and VFO OUT jacks and the accessory jack. The original 
complaint symptoms sounds suspiciously like the VFO jumper being removed. 
And in fact the same jumper being removed causes the same symptoms with a 
CORSAIR-II. SO the first question should be is that jumper in place on the 
back of the OMNI-C? Often it is missing or the new owner has overlooked 
plugging it back in. If both jumpers are in place, then the next thing to do 
is to look for a loose or disconnected connection between boards or sub 
assemblies all the way to the digital display. I have in the past seen the 
symptoms described when one connector (HFO) inside the digital display 
enclosure has been unplugged.


73 ES DX,
Gary -- AB9M



-----Original Message----- 
From: Joe
Sent: Monday, February 20, 2012 12:35 PM
To: Discussion of Ten-Tec Equipment
Subject: Re: [TenTec] OMNI C Mixer or PTO problem

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
>>>>> http://lists.contesting.com/mailman/listinfo/tentec
>>>>
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