My Omni 6+ has a failed oven in the reference oscillator and I am very
interested in replacing the item. If anyone has successfully done this
mod, I would appreciate any advice or guidance. What specific
oscillator did you use and where did you purchase it. I'm not interested
in "plowing new ground" or making a science project out of this. I just
want to get my Omni 6+ back up to good health. Thanks...
Ken, K9PGC
On 2/24/2017 11:43 AM, John Callari wrote:
Thanks for the suggestions and information...
I have to figure out if I have the time to tear her down a bit and change
the 20 MHz reference oscillator, then tune each band crystal to see if it
comes back into range.
Does anyone have a diagram that shows the layout on the board for the band
crystals? The drawings in the manual don't show which adjustment
point/crystal is for which band.
Thanks!
John
K2JNC
On Fri, Feb 24, 2017 at 9:44 AM, Dukes HiFi <dukeshifi@comcast.net> wrote:
I do not consider Omni 6 radios at EOL.
They are usually easy to fix and great performers aside from their raucous
sounding SSB receive audio.
Do you power your power supply off when you turn off your radio?
If so, you are allowing the oven to cool and there will be a significant
wait time for stabilization anyway even if the over is still working at
all. Failure of the reference crystal oven is quite common in the older
Omni 6 radios. That is why Ten Tec changed to a prepackaged 20 MHz
reference oscillator in later versions. These fail too.
Since you have SO many bad positions, it is unlikely that your problem
rests only with bad crystals anyway. More likely the reference is off
frequency snd is drifting.
Several have suggested in previous posts that you can install one of the
many prepackaged thermally compensated crystal oscillators available from
Mouser or Digikey as the reference. The frequency is 20 MHz. This is a very
good suggestion.
These devices were not available when the Omni 6 was first designed.
Installation is very easy and the end result is better than the original.
You will need to realign the crystals that are still within range but some
may need replacement. These can be had either f rom junk radios or from a
few on line crystal suppliers.
Once you follow the alignment instructions for one band that seems to
align up properly, follow through with the others and see how many of them
pull in. Chances are that most will once the reference oscillator problem
is corrected.
Gary
W0DVN
On Feb 23, 2017, at 4:58 PM, John Callari <john.callari@gmail.com>
wrote:
Hello all..
I recently acquired an Omni VI... After warming up, some bands are dead
on
(17M, 15M), some are off a little bit (40M, 80M) about 500 Hz and 20M is
off by nearly 1.5 kHz.
I've worked on some of my older Icom rigs (751, 745, 765) and was able to
re-calibrate them and re-align... but that was following the service
manuals...
Any suggestions on the best way to fix this... From what I've read and
looking at the manual, I'm guessing that my problem is with the band
crystals on the XTAL OSC/ LO board...
Any help would be much appreciated.
Thanks!
John
K2JNC
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