[time-nuts] hp10811 OCXO shipping jolt/drop survival?

[swingbyte]

Bruce Griffiths wrote:
> swingbyte wrote:
>   
>> Bruce Griffiths wrote:
>>     
>>> swingbyte wrote:
>>>  
>>>       
>>>> HI all ,
>>>> I had a 5370 A shipped to me that suffered enough of a drop/roll to
>>>> break a handle and bend the chassis such that the bottom panel had to
>>>> be modified to get it back on.  When I connected the timebase output
>>>> to the start input the frequency display is 10.0000000xx with the last
>>>> two numbers moving about quite a lot.  Could this indicate damage to
>>>> the oscillator due to the drop?  I haven't tuned up the inputs yet so
>>>> this may be an artefact of that.
>>>> Thanks
>>>>
>>>> Tim
>>>>     
>>>>         
>>> Tim
>>>
>>> What gate time was used to measure the frequency?
>>>
>>> Bruce
>>>
>>>
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>>>       
>> Hi Bruce,
>> With a 1s gate time it ranges from 9.999 999 996 to 10.000 000 012
>> MHz  The 5335 with a 1s gate time gives 10.00000101 with the last
>> digit flickering 0.   Of course what's really bad is I have two clocks
>> to check now.  The std deviation  as measured by the 5370 of the 5370
>> clock is ~1.8 kHz while the std dev of the 5335 clock is 7.8 kHz -
>> both have 10811 OCXOs.. The 5335 measures the 5370 clock  std dev as
>> 4.35mHz.  I think I'll have to check these against the Rb as I don't
>> have a GPSDO yet.
>> Thanks
>>
>> Tim
>>
>>
>>     
> Tim
>
> What was the gate time used for the STD deviation measurements?
>
> Bruce
>
>
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>   
I used a 1s gate time on the 5335 and 100ksamples to get a std deviation 
of 4.35mHz  (thats milli Hertz)  so I hope that means they are both 
(5335 & 5370) fairly stable.  With a  1s gate time on the 5370  the 
reading is 10.000 000 000  3 to 10.000 000 001 2 MHz.  which I read as 1 
part in 10E10.   
On the issue of 5370 gate time for the std dev is 1 period and 100 
samples.  The 5335 measures the clock of the 5370 as 10.000 001 06 so 
maybe one of the 10811s is 1Hz high?  The problem of two clocks.
For the performance tests I get the following results:
(13)  period 100.00 +-1ns  =>101.17ns
(14) => 101.1843ns
(15) jitter test should be <100ps => 38ps
Trigger levels range from -1.34V to +0.61V

My unit is a 2036A ser # so the first to have the 10811 as standard- 
still  only 29 years old!
What is the "ic rot"  John was talking about and what solutions are out 
there?

Thanks for your help
Tim