Some of the older rigs, particularly the Triton 4's, could lose the diodes
that develop the AGC voltage due to a static discharge or the like. Without
those diodes working, when the Drive is advanced, the rig can break into
oscillation. A way to check for oscillation is to monitor the VSWR into a
resonant antenna (better with a tuner in-line) and watching for a jump in
the SWR. Such a jump would mean that the transmitter is transmitting on
some frequency(ies) other than your fundamental.
Changing those diodes requires getting to the final PCB. There are a couple
of other diodes there which develop the SWR metering voltage... Change them
at the same time.
I do not know if the Omni VI uses a similar circuit to the earlier rigs, but
it's a place to look.
73, Mike N4NT
----- Original Message -----
From: "Paul DeWitte K9OT" <k9ot@mhtc.net>
To: <tentec@contesting.com>
Sent: Sunday, December 07, 2003 12:52 PM
Subject: [TenTec] Omni VI+ problem
> My Omni VI+ that just came back from TN a week ago failed about 10 hours
> into the 160m contest. It started tripping the power supply. I thought it
> was the power supply, so I tried a different one with a fast-acting
breaker
> in line and it did the same thing. I put it on a dummy load and when
turning
> up the power it seems to be ok until about 50 watts (meter is in the
forward
> position) and then it starts to sound like sending a bunch of dits, only
it
> is in the tune mode.
>
> I tried it on two different pieces of coax so I don't think that it is the
> coax (meter in the swr position shows no reflected power). Before I send
it
> back to TN, has anyone had this happen to them or have any ideas? I have
not
> opened it up yet so it might be something loose or visible, I hope.
>
> I was not happy, but after seeing the report from the guy that had a Orion
> failure after one contact maybe I was lucky the 6+ went as long as it did.
> Saturday morning I put the Corsair II in line and finished the contest
with
> it.
>
> Thanks for any replies.
>
> 73 de Paul K9OT
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