Hi To the extent that the oven controller is an integrator, it only integrates over a couple of seconds.
Bob > On Sep 14, 2015, at 5:58 PM, Bob Benward <[email protected]> wrote: > > Robert, > The drift has slowed down to something around 8xE-10, which is a bit over > the spec of <5E-10. But this is the single oven, I have not reassembled the > double oven yet. > > If the oven regulation was off, I would suspect I would see the EFC go back > and forth a bit, maybe a general trend up, but some retracing would be > expected. The oven control is an integrator, so unless the offset is very > large compare to the output of the thermistor, a continuously changing > offset voltage will not have a large effect on setpoint. A crystal > resonator will drift about 1-5E-8/degC, so I guess a loose temperature > control would certainly exhibit the drift I am seeing. > > Bob > > > >>>> -----Original Message----- >>>> From: time-nuts [mailto:[email protected]] On Behalf Of George >>>> Atkinson >>>> Sent: Monday, September 14, 2015 2:42 PM >>>> To: Discussion of precise time and frequency measurement >>>> Subject: Re: [time-nuts] Z380XA The saga of the aging 10811 >>>> >>>> Well, if the batch/revision of op-amps had a doping, contamination or > similar >>>> issue, the input offset could be drifting fairly constantly causing a >>>> temperature channge in one direction. >>>> >>>> Robert G8RPI. >>>> >>>> On 9 September 2015 at 04:40, Bob Benward <[email protected]> >>>> wrote: >>>> >>>>> Hi Ed, >>>>> OK, a bad oven. I can buy that. But then if the oscillator is >>>>> constantly drifting, would that not imply that the oven is constantly >>>>> changing temperature, in one direction? >>>>> >>>>> BTW, the curve is starting to flatten out. It might be flat before It >>>>> gets to 1000K counts. >>>>> >>>>> Bob >>>>> >>>>>>>> -----Original Message----- >>>>>>>> From: time-nuts [mailto:[email protected]] On Behalf Of >>>>>>>> ed breya >>>>>>>> Sent: Tuesday, September 08, 2015 10:55 AM >>>>>>>> To: [email protected] >>>>>>>> Subject: Re: [time-nuts] Z380XA The saga of the aging 10811 >>>>>>>> >>>>>>>> It could be that the inner oven temperature regulation is off a >>>>>>>> bit, or >>>>> even >>>>>>>> failed. There was a report at one of the popular time-nuts >>>>>>>> oriented >>>>> websites (I >>>>>>>> forget which one, but it's the one that had extensive coverage of >>>>>>>> the >>>>> Z3801A) >>>>>>>> about inner oven problems a few years ago. I took mine apart and >>>>>>>> found >>>>> that >>>>>>>> it had an IC of a particular date code range that was prone to > failure. >>>>> I can't >>>>>>>> recall whether I replaced it with the same type but different >>>>>>>> date, or >>>>> an >>>>>>>> alternative, but it worked just fine after that, with no tweaking >>>>>>>> of >>>>> coarse EFC >>>>>>>> needed. >>>>>>>> >>>>>>>> The IC was a dual opamp I think, that controlled the oven >>>>>>>> temperature according to the thermistor signal, and drove the > heater >>>> transistor(s). >>>>>>>> It was a fairly high performance type, but not that unusual. I >>>>>>>> think it >>>>> was a >>>>>>>> Linear Technology brand part. >>>>>>>> >>>>>>>> Ed >>>>>>>> _______________________________________________ >>>>>>>> time-nuts mailing list -- [email protected] To unsubscribe, go to >>>>>>>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>>>>>>> and follow the instructions there. >>>>>>>> ----- >>>>>>>> No virus found in this message. >>>>>>>> Checked by AVG - www.avg.com >>>>>>>> Version: 2015.0.6140 / Virus Database: 4409/10580 - Release Date: >>>>>>>> 09/05/15 >>>>> >>>>> _______________________________________________ >>>>> time-nuts mailing list -- [email protected] To unsubscribe, go to >>>>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>>>> and follow the instructions there. >>>>> >>>> _______________________________________________ >>>> time-nuts mailing list -- [email protected] To unsubscribe, go to >>>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>>> and follow the instructions there. >>>> ----- >>>> No virus found in this message. >>>> Checked by AVG - www.avg.com >>>> Version: 2015.0.6140 / Virus Database: 4419/10639 - Release Date: >>>> 09/14/15 > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
