[time-nuts] Rb cooling

Chuck Harris cfharris at erols.com
Mon Jul 18 04:40:34 UTC 2011


I understand that, but you didn't answer my question:

Has anyone seen any failures that are attributable to heat?

50 year theoretical life vs 75 theoretical year life probably
isn't going to be too significant.  1 year life vs 10 year would
be.

These GPSDO's are made to run with their ovens powered, and hot.
Surely the manufacturer took a little time to select parts that
would survive the intended operating environment.

Cooling down an oven is not a good thing, as it simply ups the
power the oven control circuitry dumps into the oven to keep it
hot.

-Chuck Harris

Neville Michie wrote:
> The manufacturers data sheet presents MTBF figures for the LPRO
> and they decline considerably with higher temperatures.
> Against that the power required decreases with rising temperature,
> so that at 19 volt supply and 40-45*C the unit takes much lower power
> and has
> still has most of its expected life.
> cheers,
> Neville Michie
>
> On 18/07/2011, at 1:59 PM, Chuck Harris wrote:
>
>> For all of this attention to cooling the oven on the Rb standards,
>> has anyone seen any failures that are attributable to heat?
>>
>> I sort of doubt it.
>>
>> -Chuck Harris




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