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

J. L. Trantham jltran at att.net
Mon Jan 15 22:18:20 EST 2018


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 1621-680100 _______________________________________________
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