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

[Bob kb8tq]

Hi

These days there is really no reason at all to play with silver mica caps in
an oscillator. A very normal ceramic NPO will do just as well. It also will 
be cheaper / easier to find. If you want to go exotic, go for glass or porcelain 
caps. It is pretty unlikely you will find them in a surplus OCXO. No real need
to stock them up as spares …..

Bob

> On Dec 8, 2017, at 11:38 AM, paul swed <paulswedb at gmail.com> wrote:
> 
> I have also done this to older oscillators and it works.
> When you look at the caps in the unit, if you are lucky somehow you may be
> able to see what type they are.
> Yes silver mica but there are various qualities and tempco's.
> Try to match the quality if at all possible.
> Otherwise guess.
> Good luck and its not the worst issue you will run into.
> Just maybe thats why you obtained the oscillator in the first place.
> Hey bad stuff is my friend.
> Regards
> Paul
> WB8TSL
> 
> On Fri, Dec 8, 2017 at 11:31 AM, Jeremy Nichols <jn6wfo at gmail.com> wrote:
> 
>> 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 <paulswedb at 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 <kb8tq at 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 at 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
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