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. _______________________________________________ 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.
