Hi Assuming it’s a unit with a 60C upper end temperature and that the 80C is the oven temperature, that seems about right. The chart in the data sheet runs from 77C to 89 C.
If it was a conventional / old style 5 MHz 5th overtone AT cut crystal the Q of the resonator would be up around 5 million on a properly done part. That can happen one of two basic ways. You can have a really low Rm or a really low Cm (of course it can. be a bit of both…). If you happen to be in the “really low Rm regime, the tuning of the crystal isn’t going to be any more crazy than one with much lower Q (and the same Cm). Yes, Co and the finish point get in there as well …. Bob > On Dec 8, 2017, at 1:35 PM, Bert Kehren via time-nuts <time-nuts@febo.com> > wrote: > > What about 80 C is that normal for an 8600? > Bert Kehren > > > In a message dated 12/8/2017 11:32:14 A.M. Eastern Standard Time, > jn6...@gmail.com writes: > > My HP-103AR frequency standard has a similar problem. I have been advised > to take it apart and replace one of the capacitors in order to bring the > frequency back into the range of adjustment. Sounds like you have the same > problem. > > Jeremy > > > On Fri, Dec 8, 2017 at 7:52 AM paul swed <paulsw...@gmail.com> wrote: > >> I took a quick look at the spec sheet. >> It appears coarse adjustment is an option M and would actually be a pot. >> That speaks to another tuning diode for coarse? Or a pot on pot >> arrangement. >> That sounds ugly. >> Regards >> Paul >> WB8TSL >> >> On Fri, Dec 8, 2017 at 10:17 AM, Bob kb8tq <kb...@n1k.org> wrote: >> >>> Hi >>> >>> It is quite possible that nothing is actually broken and that the > crystal >>> has simply drifted >>> outside the tuning range. It should be pretty easy to spot the coarse >>> tuning device once >>> the package is open. I would bet you will find a selected capacitor >> across >>> the coarse tune or in >>> series with the coarse tune. Changing the value of that cap should > bring >>> things back on >>> frequency. I would avoid changing caps across the EFC tuning diode. >>> >>> Bob >>> >>>> On Dec 8, 2017, at 8:05 AM, Ulf Kylenfall via time-nuts < >>> time-nuts@febo.com> wrote: >>>> >>>> >>>> Gentlemen, >>>> We have an Oscilloquartz OCXO 8600-3that cannot any longer be > adjusted >>> into 5,000,000 Hz.It is about 1 Hz out of 5 MHz and turning >>> coarse/fineadjustment potentiometers cannot bring the frequencyinto > its >>> specification. >>>> Oven temperature is about + 80C accordingto the thermistor and the >>> operating voltageis at 24 VDC. >>>> Have Googled but the only thing that turns upis datasheets w/o any >>> details. >>>> Before I take it apart and start lookingfor obviously broken >> components, >>> isthere anyone that has a CLIP on this unit? >>>> 73 >>>> >>>> Ulf Kylenfall - SM6GXV >>>> _______________________________________________ >>>> time-nuts mailing list -- time-nuts@febo.com >>>> To unsubscribe, go to https://www.febo.com/cgi-bin/ >>> mailman/listinfo/time-nuts >>>> and follow the instructions there. >>> >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts@febo.com >>> To unsubscribe, go to https://www.febo.com/cgi-bin/ >>> mailman/listinfo/time-nuts >>> and follow the instructions there. >>> >> _______________________________________________ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > -- > Sent from my iPad 4. > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
