[time-nuts] FE 5680A Warning

[Kasper Pedersen]

On 11/13/2011 10:36 AM, Peter Bell wrote:

> I can let you know what I've found out about these units - I got given
> a couple of dead ones and did a bit of poking around trying to get
> them working.  I didn't get that far, since one of the units was
> easily fixed (the MAX882 3.3V regulator had failed) and the other
> seems to have a faulty Rb absorption cell (it works if you swap the
> cell from the other unit into it).


Here is a pile of photos I did while fixing one of mine. In this one
the oscillator had drifted high, and wouldn't lock when warm. A tiny
nudge to C217 and it is happy, the output should sweep to about 4ppm high.
I suspect the PTC element on the xtal is dodgy too; It seems slower to
settle than the other units.

http://n1.taur.dk/fe5680a-2/

I figured they might be useful when trying to point out components and
test points.


/Kasper Pedersen