[TenTec] trouble shooting OMNI SIX<<<URGENT>>>

[Tommy]

Robert,

I'm not with Ten Tec. I also doubt that Ten Tec would respond to your post
to this reflector. The best thing to do if you wish to talk to them about
your problem, is to call the Ten Tec repair department and talk with a tech
named Don.

You described your problem quite well. I would suggest until you get the
Omni 6 repaired that you NOT try to drive your amplifier with it. There is
always the possibility your Omni 6 could damage your Hercules, and I'm sure
you don't want that to happen.

If  you don't mind, I would like to suggest a few things you could do in the
meantime. First, disconnect your Omni 6 from all of your other gear. If you
can do it, test your dummy load with another radio just to make very sure
that you dummy load is OK. It would help if you have an external SWR bridge,
but that's not completely necessary.

Next just connect your RF output from your Omni 6 directly into your dummy
load, if you have an external SWR bridge, connect that between your Omni 6
and your dummy load. This will give you a separate SWR indicator. If you do
have an extra SWR bridge and it reads an SWR that is OK but your Omni 6 SWR
indicator reads high, then you may just have a diode on the Omni 6 circuit
board that is bad. The possibility of the Omni 6 having a problem on it's
SWR circuit board is high because even with a high SWR, your power supply
over current circuit breaker is not tripping on you. Since you can get a
full 100 watts  out of the Omni 6, right now your final transistors are
probably still good (however you really do not want to run at full power
until you get the SWR problem fixed). If the SWR on the Omni 6 reads OK into
a dummy load, then you may have something wrong between the RF output
connector on the Omni 6, all the way out to your 253 tuner. You can locate
that by just removing/replacing one thing at a time. Like hook your amp
directly into the dummy load ant test your system that way. It could be
something like the coax between your Omni 6 RF out put connector and your
Hercules, or even the input circuit on your Hercules amp.

The probability of the T/R relay in the Omni 6 being bad is only a small
one, since you can get RF power output and then your receiver is still
working OK.

If you narrow your problem down to just a bad SWR reading on your Omni 6,
then there is high probability that one or both of the diodes on the SWR
circuit board is bad. But because of the physical location of the SWR
circuit board, unless your familar with the radio, I would suggest you call
Ten Tec and let them do it for you. But on the other hand I just recently
sent an Omni 6 Plus to them for some mods and it took about seven weeks to
get it back.

Good luck with it Robert,

73,

Tom - W4BQF

----- Original Message -----
From: "Linda" <dlrwild1 at comcast.net>
To: <service at tentec.com>
Cc: <tentec at contesting.com>
Sent: Monday, October 25, 2004 6:59 PM
Subject: [TenTec] trouble shooting OMNI SIX<<<URGENT>>>


Re: OMNI SIX problem

I own a Ten Tec OMNI SIX which has been upgraded to the OMNI SIX PLUS
version. It has been working perfectly for several years until a few days
ago. I noticed that my SWR readings on the transceiver meter are very high;
increasing the output power from 10 watts to 100 watts causing the SWR to be
over 3:1. As I increase the power, the SWR increases dramatically. I know
SWR readings are not a function of the power output; the SWR should be same
at any power level (10 to 100 watts barefoot with the OMNI SIX).

I have tried to load the transceiver in to several different antennas that I
know are not shorted at the antenna or in the feedline. All my other radios
work with those antennas very well. I even loaded the OMNI SIX in to my 50
ohm dummy load, but the SWR remains very high.

When using my OMNI SIX with my Hercules II amplifier, the overdrive light
comes on when the power exceeds 300 watts; the RF deck makes a crackling
sound on the lower right side of the RF deck. The amp seems to load up to
full power while increasing the drive on the transceiver. The SWR meter on
the Hercules II is also reading a high SWR. I am worried that I may have
also damaged the Hercules II RF deck in some way by loading the transceiver
in to it with high SWR? Normally, I can drive the Hercules II amp to full
500 watt power using only 50 watts or so from the OMNI SIX. I have never
observed the overdrive light coming on before, nor any of this high SWR at
the rig or at the amp.

I can receive signals using the OMNI SIX without problems on all bands; the
output seems to fold back somewhat when the SWR increases. I also hear a
slight crackling sound coming from my 961 power supply/speaker, but the crow
bar protection circuit on the 961 does not kick-in. The transceiver seems to
function normally in ever other way except the high SWR.

Can the trouble be caused from a stuck relay inside the transceiver? Can the
problem be caused from one of the circuit boards inside the radio that has a
bad solder joint, a loose cable connecting boards?

I do not believe that any of the coax jumper cables connecting the rig to
the amp, then from the amp to the auto 253 tuner are at fault.

What are your service department rates per hour on repairing amateur gear?
Do you have any repair backlog at the moment? What is the turn-around time
for repairs?

If you would like me to try some other test(s) to help diagnose my problem,
please let me know. Thank you very much for your help and time. I am looking
forward to hearing from you very soon. I have always enjoyed using and
buying Ten Tec products. I know your service department is the best!

Thank you,
Robert N. Wilderman, K3SRO
dlrwild1 at comcast.net

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