[volt-nuts] HP 3478A - Value? Quirks? Opinion?

Chris Erickson ericksonc2 at comcast.net
Mon Jan 3 19:14:02 UTC 2011

Charles has an excellent point, but as one of those eBay sellers and
hardcore volt-nut/time-nut, ask the pertinent questions regarding
traceability and procedures used to check out and calibrate the equipment in
question. Also keep in mind that "known and respected calibration lab[s]"
also charge HUNDREDS of dollars for calibration and I charge a fraction of
that in terms of markup, as I am a "secondary" source. I sell most of my
stuff calibrated to make a few extra dollars on "value added." All of my
calibrators are themselves calibrated annually by the local NIST traceable
cal lab, and I thoroughly test and run each piece of equipment I sell
through the complete calibration procedure in its manual. I also provide
full traceability data on my calibrators as well. If it doesn't work right,
won't calibrate, or I can't find the manual/don't have the equipment to
calibrate it, I won't state that it is in my auction. 


Being a time/volt nut, I also have calibration equipment of ever increasing
accuracy - for example, I'm currently overhauling a Valhalla 2720GS DC
calibrator with accuracy of 1ppm and annual drift of 3ppm to replace my
still very good Valhalla 2700C, which the local cal lab got within 1.5ppm
when freshly cal'd, but it has a drift of about 30ppm annually. 


"In one case, the seller responded and when I called the lab, they had no
record of the item." There are dishonest people everywhere, more so in this
economy. eBay is a virtual flea market and I've dealt with some real
shysters. Check out the seller and their feedback. Call the cal lab if
something doesn't seem quite right. I have 100% positive because I make good
on my promises as both a buyer and seller. 


Point being: don't completely ignore the term "calibrated" if it is not from
a known cal lab - just be well informed and ASK QUESTIONS. ASK about
traceability. ASK about procedures. ASK about calibration equipment, cal
dates, and serial numbers (all my stuff comes with this data, as with any
"known and respected calibration lab.")


Just as a side note: I don't currently have any hp/Tek/Fluke equipment for
sale, so I'm not fishing for a sale here, merely stating my case as someone
who calibrates equipment I sell and am not myself a certified lab.




> Be very, very careful about "calibrated" equipment you find 

> on-line.  Ebay is full of sellers who sell "calibrated" equipment 

> that hasn't been tested, much less adjusted, in three decades.  Some 

> "calibrated" equipment I've bought has been nonfunctional.  Now, I 

> ask the seller what lab calibrated the equipment, and on what 

> date.  Rarely will sellers answer such a question.  In one case, the 

> seller responded and when I called the lab, they had no record of the


> So, unless the seller is prepared to show you a calibration 

> certificate from a known and respected calibration lab, I'd suggest 

> ignoring any such claim when you value the item.


> Best regards,


> Charles


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