Adrian I have also a FTS 1200 that is 2 Hz off at 5 MHz and can not be tuned to 5 MHz, have not dug into it yet. But first I would check the tuning range of your OCXO depending as to which one it is the tuning voltage should go past 5 Volt. If you see peaks on the current with the Osc. above 10 MHz there has to be a problem the way the 9.xxx GHz is generated. Most likely the PLL. Bert In a message dated 6/12/2010 10:38:47 P.M. Eastern Daylight Time, [email protected] writes:
Yes, but if I press the align button when in 'failure mode', it just wont lock. And I see the 10 MHz output scanning from 10,000,002.9 at 0 volts to a hair above 10 MHz (10,000,000.08) at 5 volts. When I watch the beam current while it is scanning, I'm observing the beam current going up and down with a sharp maximum at every third scan when the tuning voltage has reached its maximum. Thus, it seems like the OCXO is the culprit. Adrian [email protected] schrieb: > If it is always stable at 5xxxxx500.32 and has the lock light on than it > has to be in the PLL. > Bert Kehren > > > In a message dated 6/12/2010 4:36:39 P.M. Eastern Daylight Time, > [email protected] writes: > > John, > > it's been a while since I digged deeper into it, but I remember having > had problems to adjust the OCXO to tuning voltage range center when the > failure mode was there. I was already suspecting an OCXO problem, but > haven't yet watched it for a long period of time. Now as you're > suspecting the same, I'm planning to run the OCXO separated from the > 4060 on an external power supply. > Btw. all of the control voltages are very close to what is hand marked > inside of the front lid (when it runs correctly). The unit is stamped > Sept, 22, 1989 and has a Rev B 4-27-90 marked EPROM. > > From my old notes I see that the 'failure mode' 5 Mhz output was > 5,000,000.500,32 Hz. It was always stable at +1E-07 off. > > Well, it would be much easier to have a spare 1000B, but I don't. > Anyone got a 1000B that I could swap in? > > Adrian > > > John Miles schrieb: > >> Sounds like the OCXO has a jumping problem, going too far out of range >> > for > >> the CS loop to correct. Have you watched it for a long period of time >> > with > >> the loop turned off? >> >> -- john, KE5FX >> >> >> >>> -----Original Message----- >>> From: [email protected] [mailto:[email protected]]on >>> Behalf Of Adrian >>> Sent: Saturday, June 12, 2010 8:03 AM >>> To: [email protected] >>> Subject: [time-nuts] Odd FTS 4060 Behavior >>> >>> >>> I have a FTS 4060 Caesium Frequency Standard that I never managed to get >>> working properly. >>> When powered on, it locks properly after some 10 minutes and keeps >>> running until it jumps off by about +1E-7. That is, the 10 MHz output >>> then reads 10,000,001 Hz, and the red alarm light is on. >>> When I tried it yesterday again, it worked for about 2 hours before the >>> shift appeared. Oddly enough, the green 'Locked' light was still on. >>> This happens every 2...20 hours. >>> >>> Any ideas what could cause that failure? >>> >>> Adrian >>> >>> _______________________________________________ >>> 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. > > _______________________________________________ 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.
