my experience is that most of the eBay meters that do not give errors are very close to spec. These old meters do not drift as much as a new meter. If you have a good 10 volts and 10k resistor calibration is a snap... verifying cal in not as easy. The high-frequency AC cal is more difficult.
On Mon, Jan 15, 2018 at 7:18 PM, J. L. Trantham <jlt...@att.net> wrote: > Forgot to add. All were purchased on theBay. > > Joe > > -----Original Message----- > From: volt-nuts [mailto:volt-nuts-boun...@febo.com] On Behalf Of J. L. > Trantham > Sent: Monday, January 15, 2018 9:12 PM > To: 'Discussion of precise voltage measurement' > Subject: Re: [volt-nuts] What's the probability of a random used 3458A > passing a Keysight calibration? > > Dave, > > I have three of these meters that have all been sent to Agilent/Keysight > for the 'Agilent/Keysight' Calibration and all have passed. Two of the > three were still 'in spec' when arrived. The third lost its calibration > when I failed to properly remove the 'CalRam' and read it. I think I tried > to read it when still 'hot' from the removal process. There is a process > that you can use via HPIB to read the contents of the CalRam but I did not > know about it at the time. I wanted to remove the chip, install a socket > and install a new chip before I sent it back to Agilent/Keysight. > > I had previously sent a Solartron 7081 to Ametek in England for > calibration and I used it to provide a 'transfer standard' to do my own 'in > house' recalibration of that 3458A and it was 'in spec' in all ranges when > it went back to Agilent, except a couple of the AC voltage ranges. > However, it was able to be successfully 'recalibrated' and was 'in spec' on > its next trip for recalibration. That was at a time when the calibrations > were done in Loveland. > > Once a 3458A has passed it's 'recalibration', you can purchase the 'Repair > Agreement' for $192 per year with up to 5 years at a time (for a slight > discount) that will allow you to send it back to Keysight for repair and > recalibration for 'no charge' other than the cost of the 'Repair Agreement' > if it ever fails during the covered time frame. > > Hope this helps. > > Joe > > -----Original Message----- > From: volt-nuts [mailto:volt-nuts-boun...@febo.com] On Behalf Of Dr. > David Kirkby > Sent: Monday, January 15, 2018 3:56 PM > To: Discussion of precise voltage measurement > Subject: [volt-nuts] What's the probability of a random used 3458A passing > a Keysight calibration? > > There's an "interesting" $5400 buy-it-now on eBay at the minute. It's > described as "Agilent 3458A 8.5 digit Multimeter CALIBRATED". > > http://www.ebay.co.uk/itm/Agilent-3458A-8-5-Digit-Multimeter-CALIBRATED/ > 232593692038 > > When one reads the description, one can see it is an HP (not Agilent) > 3458A, that was sent to Keysight for calibration, but *failed* on the 3 V 4 > MHz AC voltage. Apparently it passed on everything else. Personally I would > sell that as "spares or repair" rather than "used" and "CALIBRATED", but > different people have different ideas of what is good or not. > > Out of interest, I asked the seller what Keysight had quoted to repair > this. He said 2100 Euros, (which about $2600 USD or £1900 GBP). So to get > it in shape, it is not exactly peanuts. > > The seller said to me that he has a *lot* of experience of 3458As, and > knows that a used one has less than a 50% chance of passing a Keysight > calibration. I wonder if that's the experience of others that have bought > used 3458As and sent them to Keysight. If true, and I ever buy a 3458A, I > think I would only buy one on the condition that the seller sends it to > Keysight, I pay the calibration cost, but if it fails, I get a full refund, > including the calibration cost. > > I can understand a meter going out of spec over time, but if it can't be > sorted out without thousands of dollars spent on it, then it is not such a > good buy. But are more than 50% of 3458As like this? > > Dave > > > Dr David Kirkby Ph.D C.Eng MIET > Kirkby Microwave Ltd > Registered office: Stokes Hall Lodge, Burnham Rd, Chelmsford, Essex, CM3 > 6DT, United Kingdom Registered in England and Wales as company number > 08914892 http://www.kirkbymicrowave.co.uk/ Tel 01621'680100 / +44 > 1621-680100 _______________________________________________ > volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts > and follow the instructions there. > > _______________________________________________ > volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts > and follow the instructions there. > > _______________________________________________ > volt-nuts mailing list -- volt-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/ > mailman/listinfo/volt-nuts > and follow the instructions there. > -- *John Phillips* _______________________________________________ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.