[time-nuts] FE 5680A Warning

Peter Gottlieb nerd at verizon.net
Sat Nov 12 13:28:26 EST 2011


I am not familiar with how these units are set up.  I have a couple of 
older Ball units which simply put out 10 MHz, but these FE ones seem to 
have this external crystal oscillator?  How does that work?  I've seen 
these 5680A's for sale cheap and they come with these external 63 or so 
MHz oscillators, are they needed?  I would like a couple of small Rb osc 
units to put into comm gear but would like them self-contained without 
all sorts of external parts.  Can someone explain what's up with these?

Peter


On 11/12/2011 1:13 PM, Pete Lancashire wrote:
> They are tempting
>
> -pete (looking at bank account)
>
> On Sat, Nov 12, 2011 at 10:07 AM,<EWKehren at aol.com>  wrote:
>> I have done some more checking and identified the C field pins: one has
>> 2.5163 V, the other 2.5294 V. Would be nice to know which one gets varied in
>> units with C coil adjustment. Xtal Osc. is 60 MHz on this unit. Also has an
>> AD  9832 in it, unit is specked at 25 MHz so it does not run off the 60 MHz.
>> Bert Kehren
>>
>>
>> In a message dated 11/12/2011 12:46:36 P.M. Eastern Standard Time,
>> djl at montana.com writes:
>>
>> I just  bought a couple of 5680A's that have the same FEI p/n. They are
>> pop-riveted  to a heavy double-sided board., obviously cut off from a
>> longer board. I've  removed one of these from it's board/heatsink. There
>> are two pots on the  board, only one of them can be trimmed with the case
>> on. The sinewave  forming filter and maybe countdown chips are not there,
>> and never were.  There are three identical voltage regulators on the
>> heatsink spine.
>> I'll  be doing some more reverse engineering on these units; they were so
>> cheap I  had to have a couple! If only FEI was more helpful! hey must
>> have moved on  from these, and could put one manual out there?
>> Oh  Well!
>> Don
>>
>> EWKehren at aol.com
>>> The FE 5680A's advertised as NEW  are not NEW!  A  friend  that  made me
>>> aware of  the sale did notice clear signs of use, so I did a  closer
>>>   inspection
>>> under a Microscope and found clear indications that the  unit  has been
>>> bolted down in the past. Does work fine and I am  looking at ways to go
>>> directly
>>> to the C field to disciplin the  Rb. Does any one have info that would
>>> help
>>> to do so.
>>>   Bert Kehren  Miami
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>>
>> --
>> "Neither the voice of authority  nor the weight of reason and argument
>> are as significant as experiment, for  thence comes quiet to the mind."
>> R. Bacon
>> "If you don't know what it is,  don't poke it."
>> Ghost in the Shell
>>
>>
>> Dr. Don Latham AJ7LL
>> Six  Mile Systems LLP
>> 17850 Six Mile Road
>> POB 134
>> Huson, MT, 59846
>> VOX  406-626-4304
>> www.lightningforensics.com
>> www.sixmilesystems.com
>>
>>
>>
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