Hi They made a change on the Efratom Rb's some time around 2005 that boosted the "normal" lamp voltage by about 3 volts. Without tracing out the circuit(s) there's no way know if they just bumped the bias voltage up or what they did. An "old" lamp voltage unit probably is ok to 4 volts or so. I'm not sure if the same is true of the newer "9 volt" units.
Bob On Aug 12, 2013, at 6:52 PM, paul swed <[email protected]> wrote: > From those voltages I speculate a long life. In the various RBs I have > 2-3.5 V seems to be trouble. > Every units a bit different. When the units gets very old you will see the > lamp re-ignite. Generally this will be noticed as a significant random > phase jump. If you have a lock light it will go out for 30-60 or so seconds > until the system comes back on. > When I get an old rb I attach a cheap digital pedometer with an opto > coupler etc (Could be a FET or transistor just as easily) to the lock > signal. It increments every time the system unlocks. Humorously I call it a > loc-O-meter. > Regards > Paul > WB8TSL > > > On Mon, Aug 12, 2013 at 5:55 PM, Bob Camp <[email protected]> wrote: > >> Hi >> >> On Aug 12, 2013, at 3:21 PM, Yuri Ostry <[email protected]> wrote: >> >>> Hello, >>> >>> Tuesday, July 30, 2013, 3:03:57, Bob Camp wrote: >>> >>>>> 3) what is the typical life of such a unit? >>> >>> B> If it's run without a heat sink, about two years. >>> >>> B> If it's power off on the shelf, many decades. >>> >>> There was another "aging factor" mentioned in some documents that >>> circulate around the net. Helium can diffuse from atmosphere through >>> glass walls ans change buffer gas composition inside the cells. >> >> From what I have seen of "stored" cells - it's not a major issue. >> >>> >>> Run well cooled, >> 10 years for 90% of the units >>> >>> As I can see, my FRS-C still works well after approx 10 yrs on a cell >>> site working 24/7 and 5 yrs sitting on the shelf. But lamp voltage >>> that was recorded 5 yrs ago differs from the one that I measured >>> when I put it back to work. It is lowered little bit. >> >> The key question is - was it powered up in the cell site or simply sitting >> powered down? A *lot* of the cell site Rb's were in "emergency backup" >> applications (cell sites on trucks …). They sat around for 10 years, but >> didn't run for very long at all. >> >> Bob >> >>> >>> 73! >>> Yuri >>> UA3ATQ/KI7XJ >>> -- >>> Best regards, >>> Yuri mailto:[email protected] >>> >>> >>> _______________________________________________ >>> time-nuts mailing list -- [email protected] >>> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >> >> _______________________________________________ >> time-nuts mailing list -- [email protected] >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
