[time-nuts] FE-5680A won't lock

Bob Camp lists at rtty.us
Wed Jan 18 16:49:13 EST 2012


Hi

The lamp and sections of two of the PC boards need to be heated. More or
less - if it's covered by foam, it's heated.

Bob

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Robert Benward
Sent: Wednesday, January 18, 2012 4:01 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] FE-5680A won't lock

It would be interesting to see if you can remotely mount the Rb lamp.  The 
high temps certainly do nothing for the long term reliability of the 
electronics.  A fan is a good start.

Bob

----- Original Message ----- 
From: "Peter Gottlieb" <nerd at verizon.net>
To: <time-nuts at febo.com>
Sent: Wednesday, January 18, 2012 11:22 AM
Subject: Re: [time-nuts] FE-5680A won't lock


>   IMHO these units are designed for cooling by airflow around them and
>   minimal conduction cooling.  With my unit there is minimal heat flow
>   from the unit to the PC board it came attached to.  I am going to
>   simply cut down the board a bit and mount it in a small plenum made of
>   FR4 and use a small fan with controller.  This will be simple and get
>   heat out from all sides.  It should be the closest to the way it was
>   intended to be cooled, improved with the temp control, and still be
>   small enough to be placed into other equipment.
>
>
>   On 01/18/12, J. L. Trantham<jltran at att.net> wrote:
>
>   Use one of your 'locked' Rb as the 'standard' and then look at the 10
>   MHz
>   from the 'problem child'. See if you can adjust C217 (I think. Look at
>   the
>   archive.) to bring the 10 MHz signal close to the 'standard'.
>   Perhaps the oscillator is just out of 'range' and can be brought back
>   into
>   range where the loop can lock it. Or maybe that is what you have
>   already
>   done.
>   Both of my units get quite 'toasty'.
>   Joe
>   -----Original Message-----
>   From: [1]time-nuts-bounces at febo.com
>   [[2]mailto:time-nuts-bounces at febo.com] On
>   Behalf Of Scott Newell
>   Sent: Tuesday, January 17, 2012 10:31 PM
>   To: [3]time-nuts at febo.com
>   Subject: [time-nuts] FE-5680A won't lock
>   Just got my 3 in from nichegeek. Paid Thursday, shipped Friday,
>   arrived this evening. Wow. (Actually arrived too quickly--I don't
>   have my t-bolt running, so I can't easily do an accurate frequency
>   check.)
>   Two power up and lock in <3 minutes. One powers up, gets toasty, and
>   gives 10MHz, but no lock and no PPS.
>   The tuning config on all three read back as 0. I've set the problem
>   child to near +/- FS and about +/- 25% of tuning range: still no lock.
>   Any suggestions on what I should look for or try? I'm not quite
>   ready to throw in the towel and contact the seller.
>   --
>   newell N5TNL
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> 


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