[time-nuts] Inside a CTS 1960017 OCXO

[Alex Pummer]

Hi Dan
  how many of these oscillators have that low freq.hum?
73
KJ6UHN
Alex

On 2/27/2016 6:25 PM, Daniel Watson wrote:
> Hi,
>
> Attached is a plot of the output frequency difference from 10MHz during
> warm-up. I believe this indicates the crystal is SC cut.
>
> The VREF and EFC pins on the unit do work. The VREF is 4.1V.
>
> I probed around the board of the unit I cracked open and found a low
> frequency oscillation. It seems to vary from 40 to 90 Hz depending on where
> the unit is in the warm-up cycle, and what I'm doing to it. With the can
> cut off, the unit draws almost 50% more power than normal trying to
> maintain temperature, so it's possible this is offset from what has been
> reported in normal units.
>
> In the photos, you may have noticed two sets of large, unpopulated pads on
> the board near the output. I experimented with putting 10uF capacitors
> across those. That killed the output, but the low frequency oscillation
> could still be detected further back in the circuit.
>
>
> Dan
>
> On Sat, Feb 27, 2016 at 1:10 PM, Joseph Gray <jgray at zianet.com> wrote:
>
>> Nice teardown. I was looking at that listing just yesterday. I am tempted,
>> but don't know what I'd do with 40.
>>
>> The real question is, how do they perform?
>>
>> Joe Gray
>> W5JG
>> On Feb 27, 2016 9:48 AM, "Daniel Watson" <watsondaniel3 at gmail.com> wrote:
>>
>>> Hi,
>>>
>>> I'm sure many of you are tracking the cheap CTS 10MHz OCXOs available on
>>> eBay right now. I purchased a case of them, and decided to crack one
>> open.
>>> I took pictures along the way, thinking that might be interesting to the
>>> list. Here is the blog post if you are interested:
>>>
>>>
>>>
>> http://syncchannel.blogspot.com/2016/02/10mhz-ocxo-teardown-cts-1960017.html
>>> Comments on the internal construction of the OCXO are welcome. It seems
>>> pretty straightforward inside though.
>>>
>>>
>>> Best regards,
>>>
>>> Dan W.
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