Empathy List Archives

DD

Dr. David Kirkby

Mon, Jan 15, 2018 9:56 PM

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

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

JL

J. L. Trantham

Tue, Jan 16, 2018 3:12 AM

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@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.

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@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.

JL

J. L. Trantham

Tue, Jan 16, 2018 3:18 AM

Forgot to add. All were purchased on theBay.

Joe

-----Original Message-----
From: volt-nuts [mailto:volt-nuts-bounces@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@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.

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

JP

John Phillips

Tue, Jan 16, 2018 5:01 AM

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@att.net wrote:

Forgot to add. All were purchased on theBay.

Joe

-----Original Message-----
From: volt-nuts [mailto:volt-nuts-bounces@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@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.

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To unsubscribe, go to https://www.febo.com/cgi-bin/
mailman/listinfo/volt-nuts
and follow the instructions there.

--

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@att.net> wrote: > Forgot to add. All were purchased on theBay. > > Joe > > -----Original Message----- > From: volt-nuts [mailto:volt-nuts-bounces@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@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*

DD

Dr. David Kirkby

Tue, Jan 16, 2018 1:44 PM

On 16 January 2018 at 05:01, John Phillips john.phillips0@gmail.com wrote:

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.

Clearly in the case of the eBay item, it was the high-frequency AC volts
that was out of spec. I would imagine a number of labs that may have good
enough DC and resistance standards, may well not have good enough high
frequency AC standards for this. So maybe that meter would pass at some
other labs, who have higher uncertainties than Keysight.

Anyway, not that I can afford a 3458A, but I added up the cost of the
meter, plus the repair cost, and found it was was not much below the cost
of a new meter. I can appreciate your point about a new meter drifting
more, but I can also imagine that some of the caps in those old meters
might start to show problems. Maybe an Agilent meter might be a sweet spot

not as old as an HP, so but less stable than a newer Keysight.

Dave

On 16 January 2018 at 05:01, John Phillips <john.phillips0@gmail.com> wrote: > 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. > Clearly in the case of the eBay item, it was the high-frequency AC volts that was out of spec. I would imagine a number of labs that may have good enough DC and resistance standards, may well not have good enough high frequency AC standards for this. So maybe that meter would pass at some other labs, who have higher uncertainties than Keysight. Anyway, not that I can afford a 3458A, but I added up the cost of the meter, plus the repair cost, and found it was was not much below the cost of a new meter. I can appreciate your point about a new meter drifting more, but I can also imagine that some of the caps in those old meters might start to show problems. Maybe an Agilent meter might be a sweet spot - not as old as an HP, so but less stable than a newer Keysight. Dave

DD

Dr. David Kirkby

Tue, Jan 16, 2018 1:47 PM

On 16 January 2018 at 13:44, Dr. David Kirkby <
drkirkby@kirkbymicrowave.co.uk> wrote:

Maybe an Agilent meter might be a sweet spot - not as old as an HP, so but
less stable than a newer Keysight.

Dave

I meant to say, maybe an Agilent meter would not have the reliability
problems of an older HP, but be more stable than a new Keysight.

Does anyone know how old the units have to be to reach maximum stability?
Is it the LTZ1000A reference that improves with age, or the ADC? I assume
the zener reference, but I don't know.

Dave

On 16 January 2018 at 13:44, Dr. David Kirkby < drkirkby@kirkbymicrowave.co.uk> wrote: > Maybe an Agilent meter might be a sweet spot - not as old as an HP, so but > less stable than a newer Keysight. > > Dave > I meant to say, maybe an Agilent meter would not have the reliability problems of an older HP, but be more stable than a new Keysight. Does anyone know how old the units have to be to reach maximum stability? Is it the LTZ1000A reference that improves with age, or the ADC? I assume the zener reference, but I don't know. Dave

JL

J. L. Trantham

Tue, Jan 16, 2018 2:51 PM

I agree with the thought that older meters are more stable. That was confirmed to me by Gary Biermann who worked at Loveland.

In addition, with older meters, getting the latest (or later) firmware is desirable and, depending on the age, there are 'Service Notes' that should be complied with. The details are on the Keysight website.

Finding the 'sweet spot' is, indeed, the challenge. I have two HP and one Agilent, all made in the USA. All had 8,1 firmware.

IIRC, shortly after Agilent came into being, manufacturing moved to Malaysia and switched to SMT technology which then required assembly level replacement rather than component level repair.

Joe

-----Original Message-----
From: volt-nuts [mailto:volt-nuts-bounces@febo.com] On Behalf Of Dr. David Kirkby
Sent: Tuesday, January 16, 2018 7:48 AM
To: Discussion of precise voltage measurement
Subject: Re: [volt-nuts] What's the probability of a random used 3458A passing a Keysight calibration?

On 16 January 2018 at 13:44, Dr. David Kirkby < drkirkby@kirkbymicrowave.co.uk> wrote:

Maybe an Agilent meter might be a sweet spot - not as old as an HP, so
but less stable than a newer Keysight.

Dave

I meant to say, maybe an Agilent meter would not have the reliability problems of an older HP, but be more stable than a new Keysight.

Does anyone know how old the units have to be to reach maximum stability?
Is it the LTZ1000A reference that improves with age, or the ADC? I assume the zener reference, but I don't know.

Dave

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.

I agree with the thought that older meters are more stable. That was confirmed to me by Gary Biermann who worked at Loveland. In addition, with older meters, getting the latest (or later) firmware is desirable and, depending on the age, there are 'Service Notes' that should be complied with. The details are on the Keysight website. Finding the 'sweet spot' is, indeed, the challenge. I have two HP and one Agilent, all made in the USA. All had 8,1 firmware. IIRC, shortly after Agilent came into being, manufacturing moved to Malaysia and switched to SMT technology which then required assembly level replacement rather than component level repair. Joe -----Original Message----- From: volt-nuts [mailto:volt-nuts-bounces@febo.com] On Behalf Of Dr. David Kirkby Sent: Tuesday, January 16, 2018 7:48 AM To: Discussion of precise voltage measurement Subject: Re: [volt-nuts] What's the probability of a random used 3458A passing a Keysight calibration? On 16 January 2018 at 13:44, Dr. David Kirkby < drkirkby@kirkbymicrowave.co.uk> wrote: > Maybe an Agilent meter might be a sweet spot - not as old as an HP, so > but less stable than a newer Keysight. > > Dave > I meant to say, maybe an Agilent meter would not have the reliability problems of an older HP, but be more stable than a new Keysight. Does anyone know how old the units have to be to reach maximum stability? Is it the LTZ1000A reference that improves with age, or the ADC? I assume the zener reference, but I don't know. Dave _______________________________________________ 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.

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What's the probability of a random used 3458A passing a Keysight calibration?