[time-nuts] Question about the FE-5680A

[EWKehren at aol.com]

Sidney
 there are to many versions to count. But if you do not have 10 MHz on  the 
DB9 pin 7 you should check if the XTAL Osc. is 60 MHz. You can bring 60  
MHz out or divide internally make sure you divide first by three followed  by 
a divide by two to get a symmetrical output. 
Also check the RS 232 output some are TTL no inversion some are RS levels.  
Look for a MAX 3232 while checking for 60 MHz. 
If the XTAL is 50.255 not so easy. Will have to add an external    DDS
It it has 60 MHz and XC 9572XL chip, check pin 49 it may have 10 MHz  out.
Bert Kehren Miami
 
 
In a message dated 12/12/2013 8:57:52 A.M. Eastern Standard Time,  
sidney at jigsaw.nl writes:

Hi  all,

I recently bought a second-hand FE-5680A for some  light
experimentation via ebay.

There seems to be a number of  variants floating around. Mine in
particular lacks a J2 (where I would  expect to see the 10 MHz
connector), so I only have the DB9 J1  connector.

The unit is working, If I supply 15V over DB9 pins 1/2, the  unit heats
up, after a while pin #3 drops to indicate a lock, and pin 6  shows a 1
microsecond wide PPS that I am happy to see, since that is what I  am
most interested in.

I have a few questions:

* Does anyone  else have a unit that lacks a J2 10 MHz output? Is the
intention of such a  unit solely to provide a PPS?

* Is there a way to tell which  revision/Option I have, eg.via inquiry
on the serial port?

My unit  has no "Option" indication, all I have is FE-5680A / UN17491 /
serial nr.  27727W / Revision: B.
Without opening the unit at least, there are no other  visible markings.

* J1-1 has function +15V, J1-2 is "+15V return",  which, as I
understand it, means "ground" for the main power (I don't know  how to
interpret "provides DC return" other than that).

However,  there is also GROUND (J1-5), and there are at least the
following  signals:

- J1-3 Loop Lock Indicator (output; appears to be 5V,  with 5V
meaning "no lock")
- J1-6 Manual says "not used", but it  carries a 1 us PPS (5V)
- J1-8 RS-232 Rx (input for the  FE-5680A)
- J1-9 RS-232 Tx (output for the FE-5680A)

Should I  assume that pins 3, 6, 8, 9 are all in reference to the
ground provided by  pin 5?
Is pin 2 only "ground" for the pin 1?
Is there any relation  between the voltage levels at pin #2 and pin #5?



Any help is  greatly  appreciated!

Sidney
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