Hi One risk is that the oscillator may have drifted further than one can easily adjust it by just changing a select cap. That seems silly when we are talking about < 1 ppm, but the 8600 is an unusual OCXO. The electrodes BVA is not your run of the mill crystal. The “air gap” (actually a gap in vacuum) puts a pretty small capacitance in series with the normal crystal equivalent circuit. That cuts the practical tuning range down quite a bit….
Bob > On Dec 8, 2017, at 11:44 AM, Magnus Danielson <[email protected]> > wrote: > > Hi, > > Many include a EFC offset pot, but when you go out of range on that, as I > have for one of mine, here is no real option execept pop the lid and > potentially find a cap or change a cap. I have not seen any as I recall, but > should maybe take a look. > > However, the value for me is not to have it as sharp 5 MHz source, but very > low phase noise and high stability source as reference for measurement. The > offset error is less of a concern then, so that is why I have not spent > quality time to fix it. > > Cheers, > Magnus > > On 12/08/2017 04:52 PM, paul swed 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 <[email protected]> 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 < >>> [email protected]> 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 -- [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. >>> >> _______________________________________________ >> 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. _______________________________________________ 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.
