[time-nuts] Normal operating specs of a Morion MV89?

Alex Pummer alex at pcscons.com
Tue Sep 20 18:09:41 EDT 2016


Hi Brian

which cap is failing in the MV89 oxco-s?
73

KJ6UHN

Alex

On 9/20/2016 2:41 PM, Bryan _ wrote:
> Any tips on resoldering the can, special solder or flux required? Quite often they can be found for a good price on Ebay, from what I have read they are a  good OCXO minus the issue of the one particular cap failing.
>
> -=Bryan=-
>   
>> From: brayniac at gmail.com
>> Date: Tue, 20 Sep 2016 20:06:59 +0000
>> To: time-nuts at febo.com
>> Subject: Re: [time-nuts] Normal operating specs of a Morion MV89?
>>
>> Yes. This low output due to capacitor failure is a very common failure.
>>  From the last set of MV89a I got on the bay, all had this issue.
>>
>> I had good luck opening mine with a hot air rework station with a small
>> nozzle to blow the solder seal away. A bit of careful prying with a thin
>> flat screwdriver while it is still hot to pop the bottom from the case. The
>> capacitor is easy to get to once the outer can is removed. Hot air to
>> remove. Then tweezers and a fine point soldering pencil made for an easy
>> repair.
>>
>> Obviously, be very careful and be sure to work on an appropriate surface
>> for the amount of heat involved.
>> - Brian
>>
>> On Tue, Sep 20, 2016, 12:57 PM Bryan _ <bpl521 at outlook.com> wrote:
>>
>>> May also want to check the output amplitude. If memory serves me correct
>>> it is very common for a capacitor inside this model number to fail. It can
>>> be fixed but requires a torch or a pretty heavy duty soldering iron to get
>>> the can open.
>>> http://www.rbarrios.com/projects/MV89A/
>>>
>>> -=Bryan=-
>>>
>>>> From: listertim at gmail.com
>>>> Date: Mon, 19 Sep 2016 14:31:06 -0700
>>>> To: time-nuts at febo.com
>>>> Subject: [time-nuts] Normal operating specs of a Morion MV89?
>>>>
>>>> I recently ordered and received what claims to be a 2007 vintage
>>>> Morion MV89 from ebay (I say claimed as that what the auction item
>>>> said, but my unit is missing the identifying label on the top and just
>>>> has '2007 MV89A' written on the side in marker). I've powered it up
>>>> with a bench power supply at 12V and it's drawing 390mA at steady
>>>> state. I measured the case temperature with a ThermaPen Mk4 (not often
>>>> I get to combine the hobbies of bbq and timenuts...) which is
>>>> calibrated to +/-0.7F to be about 111F, varying somewhat with
>>>> position.
>>>>
>>>> This seems pretty hot - Is this normal ? The datasheet says it should
>>>> draw <350mA when at steady state but doesn't say what temp it should
>>>> be at. Does anyone else have info on their version to see whether this
>>>> is normal ?
>>>>
>>>> Cheers,
>>>> Tim
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