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

Peter Gottlieb nerd at verizon.net
Wed Jan 18 11:22:31 EST 2012

   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
   from the 'problem child'. See if you can adjust C217 (I think. Look at
   archive.) to bring the 10 MHz signal close to the 'standard'.
   Perhaps the oscillator is just out of 'range' and can be brought back
   range where the loop can lock it. Or maybe that is what you have
   Both of my units get quite 'toasty'.
   -----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
   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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