[time-nuts] Morion MV89A Repair

Bob Camp lists at rtty.us
Mon Feb 27 12:35:05 UTC 2012


Hi

...or my lack of experience. I think I first saw problems like these in 1975. Somehow they keep showing up :)....

Bob



On Feb 27, 2012, at 5:44 AM, EWKehren at aol.com wrote:

> Roberto
> It is called tens of years of experience
> Bert Kehren
> 
> 
> In a message dated 2/27/2012 5:16:28 A.M. Eastern Standard Time,  
> rbarrioss at msn.com writes:
> 
> Hi  Bob,
> 
> I wonder what the other oscillators that others are receiving look  like in
> the SA. Replacing all the capacitors would take a serious effort,  not sure
> if it would be justified.
> 
> Can I ask how can you know all  that by looking at the spectrum plot?
> 
> Thank you,
> Roberto  EB4EQA
> 
> -----Original Message-----
> From: time-nuts-bounces at febo.com  [mailto:time-nuts-bounces at febo.com] On
> Behalf Of Bob Camp
> Sent: sábado,  25 de febrero de 2012 23:55
> 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
> 
> 
> 
> On Feb 25,  2012, at 4:01 PM, Roberto Barrios <rbarrioss at msn.com> wrote:
> 
>> Hi all,
>> 
>> 
>> 
>> I spent this evening repairing a  MV89A that had a weak output, output 
>> cap was bad:
>> 
>> 
>> 
>> http://www.rbarrios.com/projects/MV89A
>> 
>> 
>> 
>> I also found while comparing with other two MV89A's that  they show 
>> different output spectra, as can be seen.  Test  conditions were 
>> identical but one appears much cleaner than the  others. What are the
> reasons for this?
>> 
>> 
>> 
>> Regards,
>> 
>> Roberto EB4EQA
>> 
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