[time-nuts] FE-5680A won't lock
EWKehren at aol.com
EWKehren at aol.com
Wed Jan 18 21:39:13 UTC 2012
Looking at the unit I think a lot of thought went into the total design and
cost may have been the main driver, but overall performance is
impressive.. It would be nice to have some one tackle that approach, the ribbon cable
will make it easier but still some other elements will have to considered,
like the two transistors at the lamp side. I for one plan on taking it out
of the case and use a top and bottom plate integrated with a fan cooled
plate totally surrounded by foam and hold my back plate which is the long side
at 45 C. Presently running fan test to pick the right fan / heat sink
assembly. More than any thing else temperature control will determine overall
performance and board temperature below 50 C will help life.
Bert Kehren
In a message dated 1/18/2012 4:01:41 P.M. Eastern Standard Time,
rbenward at verizon.net writes:
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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