[time-nuts] Looking for some Frequency Electronics info....

djl djl at montana.com
Mon Feb 19 19:08:44 EST 2018

start with the power supplies, and go on until morning...

On 2018-02-19 16:57, walter shawlee 2 wrote:
> I recently got a strange little 1U FEI rack mounted unit called an
> FE-7923F-100-1,
> which appears to have rear 10MHz and dual 100Mhz outputs. it is called
> a Frequency Reference Unit.
> sadly, my unit has a fault light, and no outputs. All the internal
> supplies look good, and there is an FE-83AA (10.0Mhz) and FE-1020-100
> (100Mhz) OCXO inside.  both of these work (when measured at the
> oscillators), and seem to have meaningful control including EFC, and I
> tracked down the adjustments in a sea of what seem to be prototype
> boards next to the oscillators. so, I have two good sources,
> adjustable, but still no outputs.
> the OCXO signals disappear into a set of boards with no useful
> markings as to function, and look mainly digital.
> the 100Mhz unit has only about 200mV p-p output, which seems low to
> me, the other has lots of signal. I cannot find any data on either
> unit on line or at the FEI website, so any data that is out there
> would be very welcome, so I can be sure they at least are running
> correctly.
> I am hoping to use this rack as a source of RF reference signals in
> other gear, but clearly I will have to either gut the rest of the
> circuitry and add some new buffers, or figure out the rats nest of
> hand wiring to determine why it's not working.  any help in that area
> hugely appreciated, and I can send pics to anybody interested to know
> more about the internals.
> the rear apron has AC power in, a 10MHz output SMA, a switch next to
> it that says INT/EXT REF. (set to INT), but no way to attach an
> external ref.  then there's a D-Sub filtered connector, that runs to
> the stacked digital boards, but its purpose is unknown as I cannot see
> where the connections go.  there are also two 100Mhz SMA outputs, but
> all outputs are dead, with no signal, and the front ONLINE green LED
> is dark, and the red FAULT LED is lit. the oscillators do not run to
> the rear jacks but disappear into three pcbs.
> hoping for some FEI data if anybody has some to share.
> all the best,
> walter
> --
> Walter Shawlee 2, President
> Sphere Research Corporation
> 3394 Sunnyside Rd.,  West Kelowna,  BC
> V1Z 2V4  CANADA  Phone: (250) 769-1834
> walter2 at sphere.bc.ca
> WS2: We're all in one boat, no matter how it looks to you.
> Love is all you need. (John Lennon)
> But, that doesn't mean other things don't come in handy. (WS2)
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Dr. Don Latham
PO Box 404, Frenchtown, MT, 59834
VOX: 406-626-4304

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