[time-nuts] DIY FE-5680A lobotomy (disable temp compensation)

Alexander Pummer alexpcs at ieee.org
Thu Jul 3 23:05:23 EDT 2014

keep the heat sensing very close to the heating to avoid thermal control 
oscillation ! a thermal time constant is large and no to easy to deal 
with it

On 7/3/2014 6:35 PM, Angus wrote:
> Hi Bert,
> I am thinking about testing a heat pipe on a fan cooled setup I use.
> The first temp controlled chassis I did used a peltier and works very
> well, but was a lot more work to do and is much more power hungry.
> The main problem I find is not the temp controller itself, but rather
> the change in the temperature across the chassis as the ambient
> changes. However good the temp controller is, it only controls a
> single point, but other points further away from the sensing
> thermistor can vary a lot.
> I noticed you posted a picture of a heat pipe cooler a couple of weeks
> ago - did you happen to compare the temperature across the unit with
> direct fan cooling and the heat pipe cooler, or with different heat
> pipes?
> Angus.
> On Sat, 28 Jun 2014 12:37:37 -0400 (EDT), you wrote:
>> Will someone beside us use heat pipe. Would love to have an impendent
>> input. What does it take to get a test going. Scott has done a lot of work, how
>> about some one else step up to the plate. There are a lot of time nuts out
>> there  with the 5680A,many for the first time will have a very good
>> reference and some  of our experts with proper equipment can make a big difference.
>> Bert Kehren
>> In a message dated 6/28/2014 12:20:12 P.M. Eastern Daylight Time,
>> newell+timenuts at n5tnl.com writes:
>> At 04:32  AM 6/28/2014, wb6bnq wrote:
>>> monitoring process ?  In other  words have you traced out the
>>> connections to see what is driving the  pin you think is the temperature
>> input ?
>> No. I've only traced back from  the ADC input to the voltage divider.
>>> The next big question is  have you monitored the frequency and its
>>> stability, externally, to  observe what effects are taking place when
>>> you disable this input to  the A/D ?
>> I have not.
>>> That sounds complicated and messy  but may be easier than it
>>> appears.  An appropriate container  would be:
>> It does sound messy. I don't think I'm willing to dunk one of  my units.
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