[TenTec] Omni VI Plus (564) 10 meter xmit dead

[Peter Inskeep]

Hi, John, 

Just to update you on my Omni.  I did about all the troubleshooting I know how to do, replacing a couple of transistors on the Crystal Mixer board, and then put it back together again.  The first thing I did when I got it back together was to do a master power on reset.  For a brief moment I got some power output, but then the problem recurred, and output dropped to to one watt or so.

What I think this is telling me is that the problem is somewhere in the software and or mixing sections.  They are beyond my comprehension.  So, some day it will go back to Ten-Tec for an overhaul.  

Thanks again for your help.  Take care.

Pete, no2d.


John Cox <jecox at tri-lakes.net> wrote: Hi Pete
Did you try a power on reset of the box?
My Omni VI + 160 meter band went south and ten-tec said to try that first 
and it fix it.
We tend to forget that it is a computer controlled box.
John Cox  KC0YAI
Bona, Missouri
----- Original Message ----- 
From: "Peter Inskeep" 

To: 
Sent: Friday, December 14, 2007 1:51 PM
Subject: [TenTec] Omni VI Plus (564) 10 meter xmit dead


> As last weekend's 10 meter contest started I discovered that my Omni VI + 
> 10 meter transmit is "dead."  The receive may be diminished as well, but I 
> am not sure of that. I quickly switched to another rig.
>
> When the rig is turned on from cold, ie., power supply turned off until 
> rig turned on, I get about 40 watts on both the internal meter, and on my 
> tuner's meter.  This quickly drops to virtually zero, within seconds.
>
> All other bands work fine.  All four sections of the 10 meter band are 
> dead.  Ie., 28.0 to 28.5, 28.5 to 29.0, etc.
>
> I have pulled the rig apart.  I suspect that the problem is on the Xtax 
> Osc. - L.O. Mixer board (81595).  This board is located in the box under 
> the 81595SM and 82870 boards on the top left side of the rig.  It contains 
> the band crystals and a whole bunch of switching diodes, among other 
> things.
>
> Thus, it is almost impossible for me to test anything with the rig 
> running, as I have to remove those two boards and the aluminium plate to 
> get at the Mixer board.
>
> I suspect the L.O. Mixer board because it seems to be the one place where 
> 10 meter signals are completely separated from other band signals.  In 
> fact, I am most suspicious of Q4 and/or Q5 on that board.  I will replace 
> them to see if that does it.
>
> I have checked diodes, in circuit, until my eyes are crossed.  I have 
> checked solder traces until my eyes are recrossed.  I've found nothing 
> that looks bad, and nothing that does not check continuity with my vtvm.
>
> Having bored you will all of the above, if you are still with me, I have 
> two questions.
>
> First, has anyone had the same symptom on their Omni VI Plus?   If so, can 
> you suggest a fix.
>
> Second, is there some other circuit where all four of the 10 meter 
> circuits are separate that I have not been able to discover?
>
> I have not pulled the front panel off to see if the 10 meter button is 
> "broke."  I think not because, first, it enters the "9" digit without 
> fail.  Second, it does kick in 10 meters when the rig is cold, and the 
> display does go to 10 meters.
>
> Finally, I know that the intelligent thing to do is to box it up and send 
> it to Ten-Tec.  They will not only fix this problem, but reallign it and 
> make it better than new.  If the two transistor replacements don't do it, 
> and no one on the reflector has a solution that I can implement at home, I 
> will send it back to Ten-Tec after the holidays are over and UPS is back 
> to moving cartons instead of chucking them due to the holiday rush.
>
> I am not a frequent poster to the reflector, but I do monitor it, so, if 
> you can offer any suggestions, I will be most appreciative.  My XYL's 
> solution to this is to send the rig back to Ten-Tec in trade for an Omni 
> VII.  Not a bad idea!
>
> Thanks,
> Pete, no2d.
>
>
>
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