[time-nuts] FE5680 Frequency adjustment voltage range

Bob Camp lists at cq.nu
Mon Feb 15 14:46:04 UTC 2010


In general there are no real schematics available on any of these compact Rb's. 

Many of the extra post and jumpers are related to setting up the physics package. Without a very good understanding of what they do, you really can't touch them.

Since the unit can be digitally tuned, I would guess you might find that it's set one step to high or low on the digital tune. The digital tune is easily reversed it you get it wrong ....


On Feb 15, 2010, at 9:37 AM, Raj wrote:

> I tried a 470 in parallel and the min. voltage came down to 3.6 or so. This
> did not seem to help much. 20:00 here, will try and experiment tomorrow.
> A schematic would help to understand this. Any available ?
> There seems to be more trimpots and a couple of buttons the functions
> I have no clue about.
>> Suspect thats adjusting the c field. Would not hurt especially if the unit
>> was used/surplus.
>> Try 4000.
>> On Mon, Feb 15, 2010 at 12:44 AM, Raj <vu2zap at gmail.com> wrote:
>>>       In my FE5680, I find that the trimpot for frequency adjust at one
>>> end 4.4V. The upper and lower voltages are 4.4 and 5.2 approx.
>>>       Does this mean it is at the end of its life?
>>>       There is a 4750 Resistor connected to the low end of the trimpot
>>> whose value can be reduced as a solution. Any experiences?
>>> Regards
>>> --
>>> Raj, VU2ZAP
>>> Bangalore, India.
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