[TenTec] OMNI VI Problems- any ideas?

[Steve Halliburton]

Hi, John....

I had a similar situation with my O6/3 which I also bought used.
In my case it was extreme enough so the radio would actually
stop working completely once in a while.  It turns out that the
OCXO (mail oscillator oven controlled, on the logic board)
would drift so far off that it would stop oscillating.  There was
an extremely touchy adjustment but it was almost impossible
to keep it in spec.  One possibility was that the trimmer cap
used for the adjustment was old/bad/dirty/etc.

In my case, the solution was to replace the original OCXO with
the TCXO (temperature compensated instead of oven controlled)
oscillator used in the later 6+ version.  I used the official TT part
but there are lots of other choices out there that will work also.
If you elect to use the TT part, it comes with instructions for the
replacement; the instructions don't mention disconnecting the oven
for the original crystal but I also did that.

Anyway, the result is a much more stable radio with almost no
warm-up drift.  It's much easier to put on frequency too.  If your
radio has the OCXO I'd suggest the change even if this isn't your
problem.

To check this out, try fiddling the trimmer cap for the master
oscillator.  If it seems unusually touchy, I'll bet this is your issue.
If you need more info on this, just email me.

73, Steve, WA2SOC


John Carioti wrote:
> I purchased an Omni VI about 9 months ago.  Even though the seller said the
> rig was 100%, I have noticed several things that are wrong.  Some things are
> tolerable, but a few are show stoppers.
>
> The worst problem is on CW- the rig becomes unstable after a few hours of
> operation.  Received and transmitted CW becomes extremely chirpy (on all
> bands).  The only way to correct this is to shut the rig off for 30 mins and
> let everything cool down.  Not very helpful in the middle of a contest!
>
> Has any one else run into this problem?  I've searched a bit and can't come
> up with any ideas.  I'm not an EE but can certainly do some troubleshooting
> if someone points me in the right direction.
>
> Thanks in advance!
>
> John K2ZJ
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