[time-nuts] Symmetricom chip scale atomic clock

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What can be read between the lines:

The recently acquired cash cow isn't working exactly as 
expected/advertised. We still don't have a clue when/if the fundamental 
(as in physics laws) design (we can't officially blame the cheap Chinese 
manufacturer) flaw will be fixed (manufacturer replaced), but as our 
main customer, which is used to (literally) blow up tons of (others') 
money, isn't very concerned (for now), and the profit margin is (still) 
high enough to replace (no questions asked, for the time being) the 
failed units of the other (civilian/commercial) customer(s).



On 4/24/2014 8:15 PM, Lester Veenstra wrote:
>
> Affected Products: Jackson Labs or Symmetricom time/frequency reference
> boards based on Symmetricom chip scale atomic clock, most common unit is the
> CSAC GPSDO sold by both symmetricom vendors and direct from Jackson labs
> Type of issue: Short and Long-term reliability, mfr couldn’t assure that if
> it works for 1week, 1month or 1year it is not an affected unit
> Issue: CSAC Loss of vacuum, sudden onset failure mode
> Result: CSAC unable to control the temperature, Indefinite warm-up state,
> ultimately the unit fails to reach a lock state
> Failure Rate: Vendor noted ~5% of all units, internally it has been 1 of
> maybe a dozen or less units to date
> Resolution Status: Issue acknowledged by manufacturer but not resolved,
> still affecting all current stock and current production units, Jackson Labs
> will replace the CSAC part on the board and return without a fee though
> admittedly the new part may also fail
>
>
> Details:
> While resolving an issue with a Jackson Labs CSAC GPS Disciplined Oscillator
> board, we were made aware of a reliability issue affecting all timing boards
> built around the new Symmetricom Chip Scale Atomic Clocks (a.k.a. CSAC).
> There is a fundamental design flaw that can result in the loss of vacuum in
> the CSAC, which prevents the unit from being able to effectively control the
> part’s operating temperature. The end result is a unit that is in an
> indefinite warm-up state. We were informed that all current and even
> currently produced units can fail in this way. The number we were given was
> ~5% of all units will fail, so we happened to get one of those 5%. The
> failure mode is a very sudden onset failure, for our case one day it worked
> and the next day (during a test of course) it did not. Also this is not a
> case of ‘if it works the first week then it will be fine’, it can fail
> anytime (in my case I had used it on a regular basis for several months
> prior to the failure). Our unit also spent 99% of its life in an air
> conditioned lab so certainly not subjected to even a remotely harsh
> environment.
>
>
>
> Lester B Veenstra  MØYCM K1YCM W8YCM
> lester at veenstras.com
>
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> Keyser WV 26726
> GPS: 39.336826 N  78.982287 W (Google)
> GPS: 39.33682 N  78.9823741 W (GPSDO)
>
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