[time-nuts] Oscilloquartz 3210 Cesium Standard Schematics

Giorgio Barinetti giorgio at barinetti.it
Fri Jul 27 09:55:03 EDT 2018


Good News.

I finally decided to leave it running for a few days, after a bit of inspection (changed some caps here and there, removing '77 vingage NiCs batteries, etc).

Everything is fine, no alarms, readings are ok.

But, still no Ion Current. At least at the meters, both internal and external.

Since HV generation is off a sealed module, and not directly, I'll run a measurement on the bare wire going to the tube.

https://www.ebay.it/itm/High-Voltage-PS-from-OSCILLOQUARTZ-3102-CESIUM-FREQUENCY-STANDARD-ATOMIC-CLOCK/253730161665?hash=item3b137f0401:g:djEAAMXQ01tRWP7

Voltage is quite High, around 5Kv, that probably means no load from the tube.


Any advice ?

Ciao,
Giorgio.



From: Giorgio Barinetti
Sent: giovedì 12 luglio 2018 21:49
To: time-nuts at lists.febo.com
Subject: Oscilloquartz 3210 Cesium Standard Schematics


Hi Tom,





Ok and stable were referred to the general behavior of the unit (PSU voltages, current draw).



After a 2 h warmup I've run the following test:



Frequency has then been measured with the aid of an HP 5345 clocked to a Efratom MFST GPS+Rb and is stable.



Phase noise is just around -135 @ 100 hz, output power is 10 dBm.



I did not run a full test since I have to be sure that the clock is "safe" in term of leaky capacitors

And so on. Leaving a 44 Year instruments running unattended in the lab after 20 years of sleep

Does not sound very safe to me :)



During the weekend I'll try to keep it running for 48H so I'll see what will happen.



In the meantime, thanks for your help!





Ciao,

Giorgio.





> i have been lucky to found a working Oscilloquartz 3210 Cesium ( warehouse of a telco operator ) in a good shape.



Nice find. The OSA 32xx manual that I scanned is at:



http://leapsecond.com/museum/osa3200/



That's 33 pages of "Operating and Instruction Manual". If your unit is working within spec, that's sufficient. I'll check if additional manual pages are around here somewhere, in case you need to repair it.



> seems ok and stable



Words like "ok" or "stable" are vague; try to give numerical measurements for accuracy and stability. That will help determine if your vintage Cs clock is actually working to spec or not.



Also log values over time. The ion pump should not have been zero if the unit was sitting in a warehouse for 20 years. But after some hours or days, yes, it could be near zero and this might be a good sign.



For an old, surplus, vintage Cs standard, its best to carefully monitor everything immediately after power up and continuing for several hours or days. The trend lines will tell you a great deal about the condition and prognosis of the instrument.



/tvb





----- Original Message -----

From: "Giorgio Barinetti" <giorgio at barinetti.it<http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com>>

To: <time-nuts at lists.febo.com<http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com>>

Sent: Wednesday, July 11, 2018 3:17 PM

Subject: [time-nuts] Oscilloquartz 3210 Cesium Standard Schematics





> Hi Guys,

>

> i have been lucky to found a working Oscilloquartz 3210 Cesium ( warehouse of a telco operator ) in a good shape.

>

> Powers up, seems ok and stable ( capacitors on the unit has 10/1974 date, so very old unit, serial 83), but the signal

> From the preamplifier is a little low and the Ion Pump current is 0. Like the 3 Kv supply is low ?

>

> Like to investigate but it will be nice to have a schematic.

>

> I've found a 2014 message where Tom was willing to scan the remaining part of the manual, so I'm kindly asking :)

>

>

> Thanks,

> Giorgio Barinetti



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