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.
