[time-nuts] FTS-4060M/S24 finally says LOCKed

Mark Sims holrum at hotmail.com
Fri Aug 15 17:06:34 EDT 2008

Well,  after a couple of months of continuous operation my 4060M cesium beam  unit,  it finally decided to say that it was LOCKed.  It had been operating happily,  but never said it was LOCKed.  It appeared that the auto-ALIGN subroutine in the EPROM was corrupted because it would never do the control voltage sweep to find the correct resonance peak.  It would turn of the MOD signal,  then just sit there.  You could align the unit manually and it was obviously locked (tracked GPSDO to within a few nanoseconds/day).

Today,  I walked in and found the green LOCK led had lit up.  I checked all the monitor voltages and found that my quartz oven monitor level was now 3.6V like the manual says it should be.  Previously it showed 5.0V (which I attributed to the fact that the OCXO was a FTS unit and not the usual Datum unit).  I wonder what made it decide to start showing the proper OCXO oven monitor level?

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