[time-nuts] SR620 calibration

paul swed paulswedb at gmail.com
Mon Feb 28 13:59:45 UTC 2011


You could share with all time-nuts if you uploaded to Diddiers site.
http://www.ko4bb.com/cgi-bin/manuals.pl
<http://www.ko4bb.com/cgi-bin/manuals.pl>I have placed rom images there for
HP gear as an example
Regards
Paul

On Sun, Feb 27, 2011 at 11:06 PM, Jean-Louis Oneto <
Jean-Louis.Oneto at obs-azur.fr> wrote:

> I have a scan of the schematics (A3 format), but it is rather heavy
> (3.6MB); Do you know of a place to store such a beast ? I have also a copy
> of the manual it self, but that's easier to find (I got mine from the SRS
> web site)
> Have a nice day,
> Jean-Louis Oneto
> France
> e-mail: Jean-Louis.Oneto at obs-azur.fr
>
> ----- Original Message ----- From: "J. Forster" <jfor at quik.com>
> To: "Discussion of precise time and frequency measurement" <
> time-nuts at febo.com>
> Sent: Sunday, February 27, 2011 9:27 PM
> Subject: Re: [time-nuts] SR620 calibration
>
>
>  And the schematics? I've tried without success.
>>
>> Repairing hardware w/o schematics is pretty tough.
>>
>> -John
>>
>> ===========
>>
>>
>>  Regarding the SR620 counters, I must have missed something.... It
>>> seems to me that SRS is providing about as much support as Tek or
>>> Agilent. All three offer PDF manuals and repair service. I doubt any
>>> of them have free telephone repair support for out-of-warranty
>>> products.
>>>
>>> I did a Google search for "stanford research sr620 manual pdf" and it
>>> returned a number of sites, including SRS and NASA, that had the SR620
>>> manual available for free download in PDF format. I had looked for
>>> that manual several years ago and found it then too. I did a quick
>>> compare against the paper copy of the manual and it seems to be
>>> similar although I will not say exactly the same since I didn't look
>>> that close.
>>>
>>> Since the manual has full directions for using the counter and for
>>> doing calibration, I don't understand the comments that SRS doesn't
>>> support the product and make the info available. The schematics are
>>> not included in the PDF manual but that is true of most electronic
>>> products. I expect my paper manual has them although I haven't
>>> checked.
>>>
>>> Regarding the cost of repairs, I don't care what company you talk to,
>>> they are ALL too expensive for me. But since I didn't buy the
>>> equipment new with a warranty I don't see where that is their problem.
>>> I bought my car out of warranty and I don't expect the dealer to do
>>> repairs for cheap. I have several pieces of test equipment that were
>>> labeled "Not Economical To Repair." That is why they were in the scrap
>>> bin. But they work good enough for me to use as long as I can live
>>> with the fault.
>>>
>>> I do like the counter even though I've never used any of the advanced
>>> features it has. My only complaint was the 10^-6 accuracy of the TXCO
>>> reference oscillator but since I can calibrate it at will and can use
>>> my Z3801A as an external reference, I can live with that. Somewhere
>>> along the line I need to do some research or get one of the gurus on
>>> the reflector to explain how to use the SR620 for doing Allen variance
>>> and other quality checks of the various GPSDO, rubidium, and OCXO
>>> oscillators I've collected in recent years. That is about the most
>>> advanced feature I need from the SR620.
>>>
>>> I probably don't qualify as a real time-nut since my main interest is
>>> to get my 10GHz station within a few hundred Hz of 10368.100 MHz. A
>>> few parts in 10^-11 is good enough for that..... And I would like to
>>> compare my various reference oscillators just to verify they are
>>> working as well as can be expected. But that doesn't make me a REAL
>>> time-nut.... :-)
>>>
>>> I don't intend to rekindle the previous discussion, I just don't
>>> understand the negative comments. I have several SR620 counters and
>>> for a 1GHz counter I think they are pretty good. For higher
>>> measurements I got lucky on eBay purchasing an EIP 25B counter that
>>> seems almost new. I didn't get as lucky with the HP 5340A I bought
>>> first. Expensive and unobtainable mixer parts make the 5340A
>>> unrepairable.....
>>>
>>> I do enjoy the technical discussions on the list. I particularly liked
>>> the discussion about rejuvenating a rubidium lamp. The N4IQT web page
>>> mentions the procedure but the time-nuts discussion provides a lot
>>> more detail. That should be added to a web page somewhere along with
>>> long term measurements of the results to indicate how the fix is
>>> holding. I'm sure there are a lot of people who would be interested in
>>> extending the life of their old rubidium oscillator. Having that info
>>> would certainly make me sleep better if buying a surplus rubidium on
>>> eBay.....
>>>
>>> 73, Doug Reed, N0NAS.
>>>
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>>>
>>>
>>
>>
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