My HP-103AR is low (the 1 MHz output reads 0.999 999 200 MHz) with the fine frequency adjust turned to maximum. I'm a rank amateur at this but the circuit diagram looks like a series-resonant (Pierce) oscillator. Looks like I need to replace one of the capacitors inside the oven with a smaller value.
On Fri, Dec 8, 2017 at 12:40 PM Bob kb8tq <kb...@n1k.org> wrote: > Hi > > One basic question - Is the frequency high or low? > > Assuming it’s an SC and on the lower turn, frequency low is possible > with an off temperature oven. Frequency high is unlikely unless it’s *way* > off temperature. How far off turn gives you how much delta F depends on > the inflection temperature of the crystal. It matters if it’s a “true > SC”or a > “modified SC”….. If it is a true SC and running at 80C, that’s about 10 > degrees > below inflection. There will not be a lot of frequency change in that case. > > Many (but not all) modern crystal processes tend to age positive. If that > is the > case on these parts, a frequency high is the likely outcome of “age out of > range”. > Even with a process that has a known tendency, only about 70% of them go > that direction over long periods of time. It’s not a perfect thing …. > > Bob > > > On Dec 8, 2017, at 2:34 PM, Angus <not.ag...@btinternet.com> wrote: > > > > > > The 8601 that I have was about 2 deg C off turnover when I got it, but > > I can't remember what sort or frequency error that caused. The > > temperature coefficient was terrible with that error. > > > > Angus. > > > > > > On Fri, 8 Dec 2017 13:05:14 +0000 (UTC), you 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.