[time-nuts] End-of-Range: Oscilloquartz OCXO 8600-3

[Jeremy Nichols]

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 <kb8tq at 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.again at 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
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