[time-nuts] Morion MV89A Repair

Bob Camp lists at rtty.us
Sun Feb 26 01:25:30 UTC 2012


Hi

Hit send to soon...

The AM noise could easily be another bypass issue.

Bob



On Feb 25, 2012, at 7:02 PM, "John Miles" <jmiles at pop.net> wrote:

> 
>> -----Original Message-----
>> From: time-nuts-bounces at febo.com [mailto:time-nuts-
>> bounces at febo.com] On Behalf Of Bob Camp
>> Sent: Saturday, February 25, 2012 2:55 PM
>> To: Discussion of precise time and frequency measurement
>> Subject: Re: [time-nuts] Morion MV89A Repair
>> 
>> Hi
>> 
>> The spectrum you show in the middle is the correct one. It shows the 10
> MHz
>> output and the sub-harmonics related to the 5 MHz crystal oscillator. The
>> other two are a bit broken. One appears to have a stage oscillating. The
>> other is more interesting. It has a stage oscillating that is injection
> locked to
>> the 5 MHz crystal oscillator. I suspect more than one capacitor went bad
> in
>> these OCXO's. Somebody may have sold Morion a bad reel of bypass caps.
>> 
>> Bob
> 
> Interesting.  The MV89As are very stable, but they have a lot of AM noise
> and they don't meet their PN specs (about -150 dBc/Hz at 10 kHz rather than
> -155).  I've tested a few and they all look the same in that respect.
> Sounds like replacing all of the SMT caps may be a good move.
> 
> -- john
> 
> 
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