Hi Well that puts it at 5/3 = 1.3 ppb low. The C field *should*adjust over a 2 ppb-ish range. Assuming you were near center, that puts the shift in the “couple of ppb” range. Very much the sort of thing the synth could do.
Bob > On Dec 1, 2020, at 9:44 AM, paul swed <paulsw...@gmail.com> wrote: > > Bob > I did not see your response before responding to Poul. > This morning I did flip those switches and agree that I may have something > going on in the synthesizer. The offset that showed up is a drift of 5ns in > 3 seconds and its running slow. > I do have the offsets from past measurements. Will have to look them up. > Regards > Paul. > > On Tue, Dec 1, 2020 at 8:51 AM Bob kb8tq <kb...@n1k.org> wrote: > >> Hi >> >> The C field coil resistance is low enough that you have something in the >> vicinity >> of 10mv across it. If you want to check the C field regulator, I’d just >> pop a wire and >> put a meter in series with the coil. >> >> My bet: your synthesizer has slipped a bit somewhere. I’d check it’s output >> against the table in the manual to make sure it’s still on frequency >> before I dove >> into the C field. If it’s off, the switches would be my first target. >> Rotate them a bit >> to wipe off the contacts and see if the frequency is correct when you >> reset them >> to the original position. >> >> If none of that works, I’d be happy to give your 5065 a new home :) >> >> Bob >> >>> On Nov 30, 2020, at 6:57 PM, paul swed <paulsw...@gmail.com> wrote: >>> >>> Hello to the group. >>> Was time for the quarterly Cesium and RB checks in an effort to support >> our >>> local power company. >>> I discovered that there is an issue with the HP5065a Rubidium reference. >>> >>> The frequency has slowed and the cfield pot can not make up for the jump. >>> Normally a few small tick marks are ever needed. I used 3 large marks and >>> ran out of pot. Its at 9.9. Was at 6.14. The frequency does increate with >>> the cfield adjustment. I am assuming perhaps something has happened in >> the >>> cfield regulator. >>> At least the front panel meter is indicating the +20V supply is normal. >>> But my question is this. The schematic indicate very little current >> travels >>> through the cfield coil. Guessing far less than 3 ma. by adding up >>> resistors. What I do not know yet is what is the resistance of the cfield >>> coil? I may find that I simply have dirty contacts on the A15 regulator >>> card. >>> Its possible there are other things wrong but all front panel meter >>> readings look the same as they have been for years. >>> >>> Thoughts? >>> Thank you in advance. >>> Paul >>> WB8TSL >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts@lists.febo.com >>> To unsubscribe, go to >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >>> and follow the instructions there. >> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts@lists.febo.com >> To unsubscribe, go to >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >> and follow the instructions there. >> > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.