[volt-nuts] What's the probability of a random used 3458A passing a Keysight calibration?

[John Phillips]

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 <jltran at att.net> wrote:

> Forgot to add.  All were purchased on theBay.
>
> Joe
>
> -----Original Message-----
> From: volt-nuts [mailto:volt-nuts-bounces at 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-bounces at 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
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-- 

*John Phillips*