[time-nuts] FE-5680A Mechanical Question

[Don Latham]

I have one in the 02xx, one in 03xx, and one in 04xx. I opened the 02xx
up and installed the 5v regulator hack but not the freq. adjust. There
are two pots on the board, one externally adjustable and another close
by. Both fell off(!)due to cold solder joints! fluxed 'em up and
soldered them back in place. put the thing back together, and it locked
up in about 5 min. 1 pps at 1 us wide is there, pin 6, triggers my TEK
scope just fine. Drift compared to Z3851(Ithink)about one cycle in 2-3
min. Good looking 2vp-p sinewave 1 meg 1x probe. Will try the other two
tomorrow, after install the 5v mod.
Don

Peter Bell
> The pot accessible through the hole in the casing appears is the fine
> frequency adjust pot on the older units - on these, it's connected to
> an ADC input, but as far as I can see adjusting it does nothing at
> all.
>
> There are two screws hidden under the labels that hold the top over on
> - you also need to remove the two small screws on the side that bolt
> the D-type mounting bracket in place.
>
> Regards,
>
> Pete Bell
>
>
> On Thu, Jan 12, 2012 at 10:33 AM, J. L. Trantham <jltran at att.net> wrote:
>> Boy!!!!!!!  I would have 'screwed' that up!
>>
>> Bill was correct.  Mine were 1/16th inch Allen screws, not Torx as
>> Brian
>> has, and were very easily removed.  They appear to be 3mm dia. X 5mm
>> long
>> with a 0.5mm pitch screw, in spite of having a 1/16th inch hex
>> opening.
>>
>> There were two Phillips head screws underneath that appear to hold the
>> bottom cover in place.
>>
>> On another topic, there is a small opening on the side (near the
>> 'FE'Trademark) with what appears to be a multi-turn pot inside.  What
>> is
>> that?
>>
>> Also, the 'sticker' on the top, that includes the 'FE' Trademark,
>> 'FE-5680A', etc., has a 'soft spot' on the bottom edge.  In addition,
>> there
>> is a 'soft spot' under the 'sticker' at the bottom of the front, near
>> the
>> connector, and includes the serial number.  Does anyone know what is
>> under
>> these 'stickers'?
>>
>> Thanks again.
>>
>> Joe
>>
>> -----Original Message-----
>> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com]
>> On
>> Behalf Of Brian, WA1ZMS
>> Sent: Wednesday, January 11, 2012 8:52 PM
>> To: 'Discussion of precise time and frequency measurement'
>> Subject: Re: [time-nuts] FE-5680A Mechanical Question
>>
>> My "rivets" were tiny Torx screws.
>>
>>
>> -Brian, WA1ZMS
>>
>> -----Original Message-----
>> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com]
>> On
>> Behalf Of J. L. Trantham
>> Sent: Wednesday, January 11, 2012 9:22 PM
>> To: 'Discussion of precise time and frequency measurement'
>> Subject: [time-nuts] FE-5680A Mechanical Question
>>
>> Should I ever have time to pursue the Rb unit, what happens when I
>> 'drill
>> out' all the rivets that mount the unit to the PCB that it arrived on?
>>  Any
>> reason to keep it on the PCB?
>>
>>
>>
>> Does the bottom cover come off?  Will I need to replace the rivets
>> with
>> something else to keep the bottom cover on?
>>
>>
>>
>> Thanks in advance.
>>
>>
>>
>> Joe
>>
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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."
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"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
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www.lightningforensics.com
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