Hi Randy -- sounds like your unit is in cal, based on your measurements of DCV and precision 10k resistor. Using autocal all is recommended before doing precision measurements, and I do that if it's been more than a day or two since last use. The autocal uses the internal Vref and an internal 10K resistor to do cal on everything else, so that tells you what the basic cal procedure is. I just got my 3458 back from Loveland, and that's what they did for me -- warmed it up, then ran autocal, then measured everything against a Fluke 5700, aided by an HP 3325, and another 3458. It has been 5 years since I replaced the display board (no "exchange" deal was available then AFAIK, so I don't know what's changed) and also the NVRAM board, which was dead, with one with the Snap-cap RAM chips. I did those replacements, then sent it home for cal, which was complete, since all the RAM was new. Now after 5 years, the unit passed all incoming performance tests and was sent back to me without a cal process of any kind. This tells me that an old, well-aged Vref module is a good thing. The 10VDC test had changed by a bit under 5ppm, or roughly 1ppm/year. They have a cal deal -- use code 1.090 -- press them for it -- and that saved me 30% off the normal price. I think this deal lasts until mid-September, so my recent "cal" ended up at just under $400 including shipping. I'm not sure the deal is available on new or first-time cals; my unit was in their data bank. But this is a long way of saying I don't think you need to send it for cal -- just push Auto Cal and Enter and wait about 10 minutes and you should be good to go.

The unit seems to be working so far except for one issue. After doing an ACAL, and making sure the Auto Zero is ON, I short the input leads with a copper wire shunt across the inputs and the reading is approximately -000.0023 mVDC. That seems rather high. I would expect the unit to short the input leads internally and force a zero reading during the ACAL. Anyone have any comments on this reading? Thanks, Randy On Sat, Aug 16, 2014 at 3:37 PM, Richard Moore <richiem5683@gmail.com> wrote: > Hi Randy -- sounds like your unit is in cal, based on your measurements of > DCV and precision 10k resistor. > > Using autocal all is recommended before doing precision measurements, and > I do that if it's been more than a day or two since last use. The autocal > uses the internal Vref and an internal 10K resistor to do cal on everything > else, so that tells you what the basic cal procedure is. I just got my 3458 > back from Loveland, and that's what they did for me -- warmed it up, then > ran autocal, then measured everything against a Fluke 5700, aided by an HP > 3325, and another 3458. > > It has been 5 years since I replaced the display board (no "exchange" deal > was available then AFAIK, so I don't know what's changed) and also the > NVRAM board, which was dead, with one with the Snap-cap RAM chips. I did > those replacements, then sent it home for cal, which was complete, since > all the RAM was new. Now after 5 years, the unit passed all incoming > performance tests and was sent back to me without a cal process of any > kind. This tells me that an old, well-aged Vref module is a good thing. The > 10VDC test had changed by a bit under 5ppm, or roughly 1ppm/year. > > They have a cal deal -- use code 1.090 -- press them for it -- and that > saved me 30% off the normal price. I think this deal lasts until > mid-September, so my recent "cal" ended up at just under $400 including > shipping. I'm not sure the deal is available on new or first-time cals; my > unit was in their data bank. > > But this is a long way of saying I don't think you need to send it for cal > -- just push Auto Cal and Enter and wait about 10 minutes and you should be > good to go. > _______________________________________________ > 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. >

Interesting note. After the room cooled down from about 79F to 73F, and another ACAL, the meter now reads +000.00035 mVDC, a more reasonable value, although it does bounce around a couple of tenths of a uV. Maybe that is OK? If so, then the only issue would seem to be the display has some faint pixels, which a new display should fix. Randy On Sat, Aug 16, 2014 at 9:59 PM, Randy Evans <randyevans2688@gmail.com> wrote: > > The unit seems to be working so far except for one issue. After doing an > ACAL, and making sure the Auto Zero is ON, I short the input leads with a > copper wire shunt across the inputs and the reading is approximately > -000.0023 mVDC. That seems rather high. I would expect the unit to short > the input leads internally and force a zero reading during the ACAL. > Anyone have any comments on this reading? > > Thanks, > > Randy > > > On Sat, Aug 16, 2014 at 3:37 PM, Richard Moore <richiem5683@gmail.com> > wrote: > >> Hi Randy -- sounds like your unit is in cal, based on your measurements >> of DCV and precision 10k resistor. >> >> Using autocal all is recommended before doing precision measurements, and >> I do that if it's been more than a day or two since last use. The autocal >> uses the internal Vref and an internal 10K resistor to do cal on everything >> else, so that tells you what the basic cal procedure is. I just got my 3458 >> back from Loveland, and that's what they did for me -- warmed it up, then >> ran autocal, then measured everything against a Fluke 5700, aided by an HP >> 3325, and another 3458. >> >> It has been 5 years since I replaced the display board (no "exchange" >> deal was available then AFAIK, so I don't know what's changed) and also the >> NVRAM board, which was dead, with one with the Snap-cap RAM chips. I did >> those replacements, then sent it home for cal, which was complete, since >> all the RAM was new. Now after 5 years, the unit passed all incoming >> performance tests and was sent back to me without a cal process of any >> kind. This tells me that an old, well-aged Vref module is a good thing. The >> 10VDC test had changed by a bit under 5ppm, or roughly 1ppm/year. >> >> They have a cal deal -- use code 1.090 -- press them for it -- and that >> saved me 30% off the normal price. I think this deal lasts until >> mid-September, so my recent "cal" ended up at just under $400 including >> shipping. I'm not sure the deal is available on new or first-time cals; my >> unit was in their data bank. >> >> But this is a long way of saying I don't think you need to send it for >> cal -- just push Auto Cal and Enter and wait about 10 minutes and you >> should be good to go. >> _______________________________________________ >> 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. >> > >

Randy I would guess that your display is almost certainly 'on its way out'. I had a new display fitted to my 3458A earlier this year and the difference is astounding. The display is of the vacuum-fluorescent type, and they will deteriorate over time, especially if your instrument was used in a Lab. for 24/7 - and many had been. As I live in the UK, I am not able to give you a price as it was a 'package deal' - but I'm sure you get better deal in the US. Roy -----Original Message----- From: Randy Evans Sent: Sunday, August 17, 2014 6:36 AM To: Discussion of precise voltage measurement Subject: Re: [volt-nuts] RE "new" 3458A Interesting note. After the room cooled down from about 79F to 73F, and another ACAL, the meter now reads +000.00035 mVDC, a more reasonable value, although it does bounce around a couple of tenths of a uV. Maybe that is OK? If so, then the only issue would seem to be the display has some faint pixels, which a new display should fix. Randy On Sat, Aug 16, 2014 at 9:59 PM, Randy Evans <randyevans2688@gmail.com> wrote: > > The unit seems to be working so far except for one issue. After doing an > ACAL, and making sure the Auto Zero is ON, I short the input leads with a > copper wire shunt across the inputs and the reading is approximately > -000.0023 mVDC. That seems rather high. I would expect the unit to > short > the input leads internally and force a zero reading during the ACAL. > Anyone have any comments on this reading? > > Thanks, > > Randy > > > On Sat, Aug 16, 2014 at 3:37 PM, Richard Moore <richiem5683@gmail.com> > wrote: > >> Hi Randy -- sounds like your unit is in cal, based on your measurements >> of DCV and precision 10k resistor. >> >> Using autocal all is recommended before doing precision measurements, and >> I do that if it's been more than a day or two since last use. The autocal >> uses the internal Vref and an internal 10K resistor to do cal on >> everything >> else, so that tells you what the basic cal procedure is. I just got my >> 3458 >> back from Loveland, and that's what they did for me -- warmed it up, then >> ran autocal, then measured everything against a Fluke 5700, aided by an >> HP >> 3325, and another 3458. >> >> It has been 5 years since I replaced the display board (no "exchange" >> deal was available then AFAIK, so I don't know what's changed) and also >> the >> NVRAM board, which was dead, with one with the Snap-cap RAM chips. I did >> those replacements, then sent it home for cal, which was complete, since >> all the RAM was new. Now after 5 years, the unit passed all incoming >> performance tests and was sent back to me without a cal process of any >> kind. This tells me that an old, well-aged Vref module is a good thing. >> The >> 10VDC test had changed by a bit under 5ppm, or roughly 1ppm/year. >> >> They have a cal deal -- use code 1.090 -- press them for it -- and that >> saved me 30% off the normal price. I think this deal lasts until >> mid-September, so my recent "cal" ended up at just under $400 including >> shipping. I'm not sure the deal is available on new or first-time cals; >> my >> unit was in their data bank. >> >> But this is a long way of saying I don't think you need to send it for >> cal -- just push Auto Cal and Enter and wait about 10 minutes and you >> should be good to go. >> _______________________________________________ >> 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.

Look at page #23 of the 3458A Calibration Manual.  Make yourself a "4

Before I did an ACAL I had around -000.00025 mVDC.  After ACAL I now

If I turn on the MATH function and then do 40 measurements with 100 PLC

So that correlates with my visual observation of 60 nVDC.  After an hour

Obviously do an ACAL before any precision measurements requiring low

Go to the Keysight website and go to "Technical Support" and choose

I needed a new display a few years ago.  At that time you could order

Hope this helps your decision to keep or not.

Randy: Look at page #23 of the 3458A Calibration Manual. Make yourself a "4 Terminal Short" as shown and put it in as shown. Before I did an ACAL I had around -000.00025 mVDC. After ACAL I now read +000.00002 mVDC. I did the "CAL 0" myself so I would expect that the meter should return to a low value, and it does. I do get a variation of +/- 30 nVDC using 100 PLC and just observing the variations. As I remember I have never seen a spec on the ZERO stability over temperature. If I turn on the MATH function and then do 40 measurements with 100 PLC the statistics show: Low reading -70 nVDC Mean reading -28 nVDC High reading +3.5 nVDC Total Variation 73 nVDC So that correlates with my visual observation of 60 nVDC. After an hour the room had gone up around 1 degree C. Then I observed -000.00023 mVDC. After another ACAL the reading was again +000.00002 mVDC. This particular meter has a negative tempco as the room temp goes up. Obviously do an ACAL before any precision measurements requiring low nanovolts. Go to the Keysight website and go to "Technical Support" and choose "Parts". Then enter in the "Part Number" "03458-66517" which is the replacement "03458-66507" assembly and you will see the replacement part number on the right hand side. Click on that and you will get the information about the exchange program and so on. Looks like you can just order this part online and pay for it with a credit card, but you have to create or use an existing login account. I needed a new display a few years ago. At that time you could order just the display for around $80. Being extremely good at removing and then inserting and soldering I ordered the part. The problem was that the spacing from top to bottom of the pins had changed. It went from around 1.3 inches to around 1.5 inches. So I had to bend the pins to fit my display board and then get something like 72 pins into the holes on the PC Board. It took hours. This change is probably why HP/Agilent/Keysight doesn't let you just get the display anymore but wants you to get the whole PC Board assembly. It did work just fine once installed. Hope this helps your decision to keep or not. Bill ----- Original Message ----- From: "Randy Evans" <randyevans2688@gmail.com> To: "Discussion of precise voltage measurement" <volt-nuts@febo.com> Sent: Saturday, August 16, 2014 10:36 PM Subject: Re: [volt-nuts] RE "new" 3458A > Interesting note. After the room cooled down from about 79F to 73F, and > another ACAL, the meter now reads +000.00035 mVDC, a more reasonable value, > although it does bounce around a couple of tenths of a uV. > > Maybe that is OK? If so, then the only issue would seem to be the display > has some faint pixels, which a new display should fix. > > Randy > > > On Sat, Aug 16, 2014 at 9:59 PM, Randy Evans <randyevans2688@gmail.com> > wrote: > > > > > The unit seems to be working so far except for one issue. After doing an > > ACAL, and making sure the Auto Zero is ON, I short the input leads with a > > copper wire shunt across the inputs and the reading is approximately > > -000.0023 mVDC. That seems rather high. I would expect the unit to short > > the input leads internally and force a zero reading during the ACAL. > > Anyone have any comments on this reading? > > > > Thanks, > > > > Randy > > > > > > On Sat, Aug 16, 2014 at 3:37 PM, Richard Moore <richiem5683@gmail.com> > > wrote: > > > >> Hi Randy -- sounds like your unit is in cal, based on your measurements > >> of DCV and precision 10k resistor. > >> > >> Using autocal all is recommended before doing precision measurements, and > >> I do that if it's been more than a day or two since last use. The autocal > >> uses the internal Vref and an internal 10K resistor to do cal on everything > >> else, so that tells you what the basic cal procedure is. I just got my 3458 > >> back from Loveland, and that's what they did for me -- warmed it up, then > >> ran autocal, then measured everything against a Fluke 5700, aided by an HP > >> 3325, and another 3458. > >> > >> It has been 5 years since I replaced the display board (no "exchange" > >> deal was available then AFAIK, so I don't know what's changed) and also the > >> NVRAM board, which was dead, with one with the Snap-cap RAM chips. I did > >> those replacements, then sent it home for cal, which was complete, since > >> all the RAM was new. Now after 5 years, the unit passed all incoming > >> performance tests and was sent back to me without a cal process of any > >> kind. This tells me that an old, well-aged Vref module is a good thing. The > >> 10VDC test had changed by a bit under 5ppm, or roughly 1ppm/year. > >> > >> They have a cal deal -- use code 1.090 -- press them for it -- and that > >> saved me 30% off the normal price. I think this deal lasts until > >> mid-September, so my recent "cal" ended up at just under $400 including > >> shipping. I'm not sure the deal is available on new or first-time cals; my > >> unit was in their data bank. > >> > >> But this is a long way of saying I don't think you need to send it for > >> cal -- just push Auto Cal and Enter and wait about 10 minutes and you > >> should be good to go. > >> _______________________________________________ > >> 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.

 Look at page #23 of the 3458A Calibration Manual.  Make yourself a "4

 Before I did an ACAL I had around -000.00025 mVDC.  After ACAL I now

 If I turn on the MATH function and then do 40 measurements with 100 PLC

 So that correlates with my visual observation of 60 nVDC.  After an

 Obviously do an ACAL before any precision measurements requiring low

 Go to the Keysight website and go to "Technical Support" and choose

 I needed a new display a few years ago.  At that time you could order

 Hope this helps your decision to keep or not.

Bill, I installed the U-short and executed the BLUE-C-0 front panel command and I get an ERR on the display. I assume this is not good. Did I do this correctly? Thanks, Randy On Sun, Aug 17, 2014 at 10:49 AM, Bill Gold <wpgold3637@att.net> wrote: > Randy: > > Look at page #23 of the 3458A Calibration Manual. Make yourself a "4 > Terminal Short" as shown and put it in as shown. > > Before I did an ACAL I had around -000.00025 mVDC. After ACAL I now > read +000.00002 mVDC. I did the "CAL 0" myself so I would expect that the > meter should return to a low value, and it does. I do get a variation of > +/- 30 nVDC using 100 PLC and just observing the variations. As I remember > I have never seen a spec on the ZERO stability over temperature. > > If I turn on the MATH function and then do 40 measurements with 100 PLC > the statistics show: > > Low reading -70 nVDC > Mean reading -28 nVDC > High reading +3.5 nVDC > Total Variation 73 nVDC > > So that correlates with my visual observation of 60 nVDC. After an > hour > the room had gone up around 1 degree C. Then I observed -000.00023 mVDC. > After another ACAL the reading was again +000.00002 mVDC. This particular > meter has a negative tempco as the room temp goes up. > > Obviously do an ACAL before any precision measurements requiring low > nanovolts. > > Go to the Keysight website and go to "Technical Support" and choose > "Parts". Then enter in the "Part Number" "03458-66517" which is the > replacement "03458-66507" assembly and you will see the replacement part > number on the right hand side. Click on that and you will get the > information about the exchange program and so on. Looks like you can just > order this part online and pay for it with a credit card, but you have to > create or use an existing login account. > > I needed a new display a few years ago. At that time you could order > just the display for around $80. Being extremely good at removing and then > inserting and soldering I ordered the part. The problem was that the > spacing from top to bottom of the pins had changed. It went from around > 1.3 > inches to around 1.5 inches. So I had to bend the pins to fit my display > board and then get something like 72 pins into the holes on the PC Board. > It took hours. This change is probably why HP/Agilent/Keysight doesn't let > you just get the display anymore but wants you to get the whole PC Board > assembly. It did work just fine once installed. > > Hope this helps your decision to keep or not. > > Bill > > > > ----- Original Message ----- > From: "Randy Evans" <randyevans2688@gmail.com> > To: "Discussion of precise voltage measurement" <volt-nuts@febo.com> > Sent: Saturday, August 16, 2014 10:36 PM > Subject: Re: [volt-nuts] RE "new" 3458A > > > > Interesting note. After the room cooled down from about 79F to 73F, and > > another ACAL, the meter now reads +000.00035 mVDC, a more reasonable > value, > > although it does bounce around a couple of tenths of a uV. > > > > Maybe that is OK? If so, then the only issue would seem to be the > display > > has some faint pixels, which a new display should fix. > > > > Randy > > > > > > On Sat, Aug 16, 2014 at 9:59 PM, Randy Evans <randyevans2688@gmail.com> > > wrote: > > > > > > > > The unit seems to be working so far except for one issue. After doing > an > > > ACAL, and making sure the Auto Zero is ON, I short the input leads > with > a > > > copper wire shunt across the inputs and the reading is approximately > > > -000.0023 mVDC. That seems rather high. I would expect the unit to > short > > > the input leads internally and force a zero reading during the ACAL. > > > Anyone have any comments on this reading? > > > > > > Thanks, > > > > > > Randy > > > > > > > > > On Sat, Aug 16, 2014 at 3:37 PM, Richard Moore <richiem5683@gmail.com> > > > wrote: > > > > > >> Hi Randy -- sounds like your unit is in cal, based on your > measurements > > >> of DCV and precision 10k resistor. > > >> > > >> Using autocal all is recommended before doing precision measurements, > and > > >> I do that if it's been more than a day or two since last use. The > autocal > > >> uses the internal Vref and an internal 10K resistor to do cal on > everything > > >> else, so that tells you what the basic cal procedure is. I just got my > 3458 > > >> back from Loveland, and that's what they did for me -- warmed it up, > then > > >> ran autocal, then measured everything against a Fluke 5700, aided by > an > HP > > >> 3325, and another 3458. > > >> > > >> It has been 5 years since I replaced the display board (no "exchange" > > >> deal was available then AFAIK, so I don't know what's changed) and > also > the > > >> NVRAM board, which was dead, with one with the Snap-cap RAM chips. I > did > > >> those replacements, then sent it home for cal, which was complete, > since > > >> all the RAM was new. Now after 5 years, the unit passed all incoming > > >> performance tests and was sent back to me without a cal process of any > > >> kind. This tells me that an old, well-aged Vref module is a good > thing. > The > > >> 10VDC test had changed by a bit under 5ppm, or roughly 1ppm/year. > > >> > > >> They have a cal deal -- use code 1.090 -- press them for it -- and > that > > >> saved me 30% off the normal price. I think this deal lasts until > > >> mid-September, so my recent "cal" ended up at just under $400 > including > > >> shipping. I'm not sure the deal is available on new or first-time > cals; > my > > >> unit was in their data bank. > > >> > > >> But this is a long way of saying I don't think you need to send it for > > >> cal -- just push Auto Cal and Enter and wait about 10 minutes and you > > >> should be good to go. > > >> _______________________________________________ > > >> 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. >

You are doing a ZERO calibration on the meter rather than a ACAL.  You

 Look at page #23 of the 3458A Calibration Manual.  Make yourself a

 Before I did an ACAL I had around -000.00025 mVDC.  After ACAL I now

 If I turn on the MATH function and then do 40 measurements with 100

 So that correlates with my visual observation of 60 nVDC.  After an

 Obviously do an ACAL before any precision measurements requiring low

 Go to the Keysight website and go to "Technical Support" and choose

 I needed a new display a few years ago.  At that time you could

 Hope this helps your decision to keep or not.

Randy: You are doing a ZERO calibration on the meter rather than a ACAL. You have to give it a password after the "0" and then it will do the ZERO calibration. Usually the password is "3458" and comes from the factory that way. But someone could have changed it in the past. You can do this from the front panel menu using the SECURE command. But there is a jumper inside the 3458A which disables the request for a password so that you can do any CAL or reset the password to what you want. So everything is working as expected. The jumper is JM600 on the outguard processor board 66505 or 66515 on the left of the meter inside. Try "3458" first as most are set to this password. Read the Calibration Manual pg. #8 for how to get inside of the meter. You will need two sizes of a PosiDrive type screwdrivers to accomplish this. Again in the Cal Manual. Bill ----- Original Message ----- From: "Randy Evans" <randyevans2688@gmail.com> To: "Discussion of precise voltage measurement" <volt-nuts@febo.com> Sent: Sunday, August 17, 2014 11:22 AM Subject: Re: [volt-nuts] RE "new" 3458A > Bill, > > I installed the U-short and executed the BLUE-C-0 front panel command and I > get an ERR on the display. I assume this is not good. Did I do this > correctly? > > Thanks, > > Randy > > > On Sun, Aug 17, 2014 at 10:49 AM, Bill Gold <wpgold3637@att.net> wrote: > > > Randy: > > > > Look at page #23 of the 3458A Calibration Manual. Make yourself a "4 > > Terminal Short" as shown and put it in as shown. > > > > Before I did an ACAL I had around -000.00025 mVDC. After ACAL I now > > read +000.00002 mVDC. I did the "CAL 0" myself so I would expect that the > > meter should return to a low value, and it does. I do get a variation of > > +/- 30 nVDC using 100 PLC and just observing the variations. As I remember > > I have never seen a spec on the ZERO stability over temperature. > > > > If I turn on the MATH function and then do 40 measurements with 100 PLC > > the statistics show: > > > > Low reading -70 nVDC > > Mean reading -28 nVDC > > High reading +3.5 nVDC > > Total Variation 73 nVDC > > > > So that correlates with my visual observation of 60 nVDC. After an > > hour > > the room had gone up around 1 degree C. Then I observed -000.00023 mVDC. > > After another ACAL the reading was again +000.00002 mVDC. This particular > > meter has a negative tempco as the room temp goes up. > > > > Obviously do an ACAL before any precision measurements requiring low > > nanovolts. > > > > Go to the Keysight website and go to "Technical Support" and choose > > "Parts". Then enter in the "Part Number" "03458-66517" which is the > > replacement "03458-66507" assembly and you will see the replacement part > > number on the right hand side. Click on that and you will get the > > information about the exchange program and so on. Looks like you can just > > order this part online and pay for it with a credit card, but you have to > > create or use an existing login account. > > > > I needed a new display a few years ago. At that time you could order > > just the display for around $80. Being extremely good at removing and then > > inserting and soldering I ordered the part. The problem was that the > > spacing from top to bottom of the pins had changed. It went from around > > 1.3 > > inches to around 1.5 inches. So I had to bend the pins to fit my display > > board and then get something like 72 pins into the holes on the PC Board. > > It took hours. This change is probably why HP/Agilent/Keysight doesn't let > > you just get the display anymore but wants you to get the whole PC Board > > assembly. It did work just fine once installed. > > > > Hope this helps your decision to keep or not. > > > > Bill > > > > > > > > ----- Original Message ----- > > From: "Randy Evans" <randyevans2688@gmail.com> > > To: "Discussion of precise voltage measurement" <volt-nuts@febo.com> > > Sent: Saturday, August 16, 2014 10:36 PM > > Subject: Re: [volt-nuts] RE "new" 3458A > > > > > > > Interesting note. After the room cooled down from about 79F to 73F, and > > > another ACAL, the meter now reads +000.00035 mVDC, a more reasonable > > value, > > > although it does bounce around a couple of tenths of a uV. > > > > > > Maybe that is OK? If so, then the only issue would seem to be the > > display > > > has some faint pixels, which a new display should fix. > > > > > > Randy > > > > > > > > > On Sat, Aug 16, 2014 at 9:59 PM, Randy Evans <randyevans2688@gmail.com> > > > wrote: > > > > > > > > > > > The unit seems to be working so far except for one issue. After doing > > an > > > > ACAL, and making sure the Auto Zero is ON, I short the input leads > > with > > a > > > > copper wire shunt across the inputs and the reading is approximately > > > > -000.0023 mVDC. That seems rather high. I would expect the unit to > > short > > > > the input leads internally and force a zero reading during the ACAL. > > > > Anyone have any comments on this reading? > > > > > > > > Thanks, > > > > > > > > Randy > > > > > > > > > > > > On Sat, Aug 16, 2014 at 3:37 PM, Richard Moore <richiem5683@gmail.com> > > > > wrote: > > > > > > > >> Hi Randy -- sounds like your unit is in cal, based on your > > measurements > > > >> of DCV and precision 10k resistor. > > > >> > > > >> Using autocal all is recommended before doing precision measurements, > > and > > > >> I do that if it's been more than a day or two since last use. The > > autocal > > > >> uses the internal Vref and an internal 10K resistor to do cal on > > everything > > > >> else, so that tells you what the basic cal procedure is. I just got my > > 3458 > > > >> back from Loveland, and that's what they did for me -- warmed it up, > > then > > > >> ran autocal, then measured everything against a Fluke 5700, aided by > > an > > HP > > > >> 3325, and another 3458. > > > >> > > > >> It has been 5 years since I replaced the display board (no "exchange" > > > >> deal was available then AFAIK, so I don't know what's changed) and > > also > > the > > > >> NVRAM board, which was dead, with one with the Snap-cap RAM chips. I > > did > > > >> those replacements, then sent it home for cal, which was complete, > > since > > > >> all the RAM was new. Now after 5 years, the unit passed all incoming > > > >> performance tests and was sent back to me without a cal process of any > > > >> kind. This tells me that an old, well-aged Vref module is a good > > thing. > > The > > > >> 10VDC test had changed by a bit under 5ppm, or roughly 1ppm/year. > > > >> > > > >> They have a cal deal -- use code 1.090 -- press them for it -- and > > that > > > >> saved me 30% off the normal price. I think this deal lasts until > > > >> mid-September, so my recent "cal" ended up at just under $400 > > including > > > >> shipping. I'm not sure the deal is available on new or first-time > > cals; > > my > > > >> unit was in their data bank. > > > >> > > > >> But this is a long way of saying I don't think you need to send it for > > > >> cal -- just push Auto Cal and Enter and wait about 10 minutes and you > > > >> should be good to go. > > > >> _______________________________________________ > > > >> 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. > > > _______________________________________________ > 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.

 You are doing a ZERO calibration on the meter rather than a ACAL.  You

 Look at page #23 of the 3458A Calibration Manual.  Make yourself a

 Before I did an ACAL I had around -000.00025 mVDC.  After ACAL I

 If I turn on the MATH function and then do 40 measurements with 100

 So that correlates with my visual observation of 60 nVDC.  After an

 Obviously do an ACAL before any precision measurements requiring

 Go to the Keysight website and go to "Technical Support" and choose

 I needed a new display a few years ago.  At that time you could

 Hope this helps your decision to keep or not.

Bill, You are very helpful and I really appreciate it. I entered BLUE-C-03458 and I still get the ERR message (106, "OUT OF RANGE -- CAL secured"). That would be consistent with what you are saying. I guess its no reason to panic yet. I'm not sure how to use the SECURE command. I guess it's time to open it up but I will probably have to get some PosiDrive screwdrivers. Thanks, Randy On Sun, Aug 17, 2014 at 11:39 AM, Bill Gold <wpgold3637@att.net> wrote: > Randy: > > You are doing a ZERO calibration on the meter rather than a ACAL. You > have to give it a password after the "0" and then it will do the ZERO > calibration. Usually the password is "3458" and comes from the factory > that > way. But someone could have changed it in the past. You can do this from > the front panel menu using the SECURE command. But there is a jumper > inside > the 3458A which disables the request for a password so that you can do any > CAL or reset the password to what you want. So everything is working as > expected. The jumper is JM600 on the outguard processor board 66505 or > 66515 on the left of the meter inside. Try "3458" first as most are set to > this password. Read the Calibration Manual pg. #8 for how to get inside of > the meter. You will need two sizes of a PosiDrive type screwdrivers to > accomplish this. Again in the Cal Manual. > > Bill > > ----- Original Message ----- > From: "Randy Evans" <randyevans2688@gmail.com> > To: "Discussion of precise voltage measurement" <volt-nuts@febo.com> > Sent: Sunday, August 17, 2014 11:22 AM > Subject: Re: [volt-nuts] RE "new" 3458A > > > > Bill, > > > > I installed the U-short and executed the BLUE-C-0 front panel command and > I > > get an ERR on the display. I assume this is not good. Did I do this > > correctly? > > > > Thanks, > > > > Randy > > > > > > On Sun, Aug 17, 2014 at 10:49 AM, Bill Gold <wpgold3637@att.net> wrote: > > > > > Randy: > > > > > > Look at page #23 of the 3458A Calibration Manual. Make yourself a > "4 > > > Terminal Short" as shown and put it in as shown. > > > > > > Before I did an ACAL I had around -000.00025 mVDC. After ACAL I > now > > > read +000.00002 mVDC. I did the "CAL 0" myself so I would expect that > the > > > meter should return to a low value, and it does. I do get a variation > of > > > +/- 30 nVDC using 100 PLC and just observing the variations. As I > remember > > > I have never seen a spec on the ZERO stability over temperature. > > > > > > If I turn on the MATH function and then do 40 measurements with 100 > PLC > > > the statistics show: > > > > > > Low reading -70 nVDC > > > Mean reading -28 nVDC > > > High reading +3.5 nVDC > > > Total Variation 73 nVDC > > > > > > So that correlates with my visual observation of 60 nVDC. After an > > > hour > > > the room had gone up around 1 degree C. Then I observed -000.00023 > mVDC. > > > After another ACAL the reading was again +000.00002 mVDC. This > particular > > > meter has a negative tempco as the room temp goes up. > > > > > > Obviously do an ACAL before any precision measurements requiring > low > > > nanovolts. > > > > > > Go to the Keysight website and go to "Technical Support" and choose > > > "Parts". Then enter in the "Part Number" "03458-66517" which is the > > > replacement "03458-66507" assembly and you will see the replacement > part > > > number on the right hand side. Click on that and you will get the > > > information about the exchange program and so on. Looks like you can > just > > > order this part online and pay for it with a credit card, but you have > to > > > create or use an existing login account. > > > > > > I needed a new display a few years ago. At that time you could > order > > > just the display for around $80. Being extremely good at removing and > then > > > inserting and soldering I ordered the part. The problem was that the > > > spacing from top to bottom of the pins had changed. It went from > around > > > 1.3 > > > inches to around 1.5 inches. So I had to bend the pins to fit my > display > > > board and then get something like 72 pins into the holes on the PC > Board. > > > It took hours. This change is probably why HP/Agilent/Keysight doesn't > let > > > you just get the display anymore but wants you to get the whole PC > Board > > > assembly. It did work just fine once installed. > > > > > > Hope this helps your decision to keep or not. > > > > > > Bill > > > > > > > > > > > > ----- Original Message ----- > > > From: "Randy Evans" <randyevans2688@gmail.com> > > > To: "Discussion of precise voltage measurement" <volt-nuts@febo.com> > > > Sent: Saturday, August 16, 2014 10:36 PM > > > Subject: Re: [volt-nuts] RE "new" 3458A > > > > > > > > > > Interesting note. After the room cooled down from about 79F to 73F, > and > > > > another ACAL, the meter now reads +000.00035 mVDC, a more reasonable > > > value, > > > > although it does bounce around a couple of tenths of a uV. > > > > > > > > Maybe that is OK? If so, then the only issue would seem to be the > > > display > > > > has some faint pixels, which a new display should fix. > > > > > > > > Randy > > > > > > > > > > > > On Sat, Aug 16, 2014 at 9:59 PM, Randy Evans > <randyevans2688@gmail.com> > > > > wrote: > > > > > > > > > > > > > > The unit seems to be working so far except for one issue. After > doing > > > an > > > > > ACAL, and making sure the Auto Zero is ON, I short the input leads > > > with > > > a > > > > > copper wire shunt across the inputs and the reading is > approximately > > > > > -000.0023 mVDC. That seems rather high. I would expect the unit > to > > > short > > > > > the input leads internally and force a zero reading during the > ACAL. > > > > > Anyone have any comments on this reading? > > > > > > > > > > Thanks, > > > > > > > > > > Randy > > > > > > > > > > > > > > > On Sat, Aug 16, 2014 at 3:37 PM, Richard Moore > <richiem5683@gmail.com> > > > > > wrote: > > > > > > > > > >> Hi Randy -- sounds like your unit is in cal, based on your > > > measurements > > > > >> of DCV and precision 10k resistor. > > > > >> > > > > >> Using autocal all is recommended before doing precision > measurements, > > > and > > > > >> I do that if it's been more than a day or two since last use. The > > > autocal > > > > >> uses the internal Vref and an internal 10K resistor to do cal on > > > everything > > > > >> else, so that tells you what the basic cal procedure is. I just > got > my > > > 3458 > > > > >> back from Loveland, and that's what they did for me -- warmed it > up, > > > then > > > > >> ran autocal, then measured everything against a Fluke 5700, aided > by > > > an > > > HP > > > > >> 3325, and another 3458. > > > > >> > > > > >> It has been 5 years since I replaced the display board (no > "exchange" > > > > >> deal was available then AFAIK, so I don't know what's changed) and > > > also > > > the > > > > >> NVRAM board, which was dead, with one with the Snap-cap RAM chips. > I > > > did > > > > >> those replacements, then sent it home for cal, which was complete, > > > since > > > > >> all the RAM was new. Now after 5 years, the unit passed all > incoming > > > > >> performance tests and was sent back to me without a cal process of > any > > > > >> kind. This tells me that an old, well-aged Vref module is a good > > > thing. > > > The > > > > >> 10VDC test had changed by a bit under 5ppm, or roughly 1ppm/year. > > > > >> > > > > >> They have a cal deal -- use code 1.090 -- press them for it -- and > > > that > > > > >> saved me 30% off the normal price. I think this deal lasts until > > > > >> mid-September, so my recent "cal" ended up at just under $400 > > > including > > > > >> shipping. I'm not sure the deal is available on new or first-time > > > cals; > > > my > > > > >> unit was in their data bank. > > > > >> > > > > >> But this is a long way of saying I don't think you need to send it > for > > > > >> cal -- just push Auto Cal and Enter and wait about 10 minutes and > you > > > > >> should be good to go. > > > > >> _______________________________________________ > > > > >> 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. > > > > > _______________________________________________ > > 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. >

Randy, I think there is a comma between the 0 and the password. Todd On Sun, Aug 17, 2014 at 3:25 PM, Randy Evans <randyevans2688@gmail.com> wrote: > Bill, > > You are very helpful and I really appreciate it. > > I entered BLUE-C-03458 and I still get the ERR message (106, "OUT OF RANGE > -- CAL secured"). That would be consistent with what you are saying. I > guess its no reason to panic yet. > >

 You are doing a ZERO calibration on the meter rather than a ACAL.

 Look at page #23 of the 3458A Calibration Manual.  Make yourself

 Before I did an ACAL I had around -000.00025 mVDC.  After ACAL I

 If I turn on the MATH function and then do 40 measurements with

 So that correlates with my visual observation of 60 nVDC.  After

 Obviously do an ACAL before any precision measurements requiring

 Go to the Keysight website and go to "Technical Support" and

 I needed a new display a few years ago.  At that time you could

 Hope this helps your decision to keep or not.

You need a comma "," between the "0" and the "3458". So blu C "CAL 0,3458" "Enter". See pg. # 64 of the CAL Manual for the syntax. Bill ----- Original Message ----- From: "Randy Evans" <randyevans2688@gmail.com> To: "Discussion of precise voltage measurement" <volt-nuts@febo.com> Sent: Sunday, August 17, 2014 12:25 PM Subject: Re: [volt-nuts] RE "new" 3458A > Bill, > > You are very helpful and I really appreciate it. > > I entered BLUE-C-03458 and I still get the ERR message (106, "OUT OF RANGE > -- CAL secured"). That would be consistent with what you are saying. I > guess its no reason to panic yet. > > I'm not sure how to use the SECURE command. I guess it's time to open it > up but I will probably have to get some PosiDrive screwdrivers. > > Thanks, > > Randy > > > On Sun, Aug 17, 2014 at 11:39 AM, Bill Gold <wpgold3637@att.net> wrote: > > > Randy: > > > > You are doing a ZERO calibration on the meter rather than a ACAL. You > > have to give it a password after the "0" and then it will do the ZERO > > calibration. Usually the password is "3458" and comes from the factory > > that > > way. But someone could have changed it in the past. You can do this from > > the front panel menu using the SECURE command. But there is a jumper > > inside > > the 3458A which disables the request for a password so that you can do any > > CAL or reset the password to what you want. So everything is working as > > expected. The jumper is JM600 on the outguard processor board 66505 or > > 66515 on the left of the meter inside. Try "3458" first as most are set to > > this password. Read the Calibration Manual pg. #8 for how to get inside of > > the meter. You will need two sizes of a PosiDrive type screwdrivers to > > accomplish this. Again in the Cal Manual. > > > > Bill > > > > ----- Original Message ----- > > From: "Randy Evans" <randyevans2688@gmail.com> > > To: "Discussion of precise voltage measurement" <volt-nuts@febo.com> > > Sent: Sunday, August 17, 2014 11:22 AM > > Subject: Re: [volt-nuts] RE "new" 3458A > > > > > > > Bill, > > > > > > I installed the U-short and executed the BLUE-C-0 front panel command and > > I > > > get an ERR on the display. I assume this is not good. Did I do this > > > correctly? > > > > > > Thanks, > > > > > > Randy > > > > > > > > > On Sun, Aug 17, 2014 at 10:49 AM, Bill Gold <wpgold3637@att.net> wrote: > > > > > > > Randy: > > > > > > > > Look at page #23 of the 3458A Calibration Manual. Make yourself a > > "4 > > > > Terminal Short" as shown and put it in as shown. > > > > > > > > Before I did an ACAL I had around -000.00025 mVDC. After ACAL I > > now > > > > read +000.00002 mVDC. I did the "CAL 0" myself so I would expect that > > the > > > > meter should return to a low value, and it does. I do get a variation > > of > > > > +/- 30 nVDC using 100 PLC and just observing the variations. As I > > remember > > > > I have never seen a spec on the ZERO stability over temperature. > > > > > > > > If I turn on the MATH function and then do 40 measurements with 100 > > PLC > > > > the statistics show: > > > > > > > > Low reading -70 nVDC > > > > Mean reading -28 nVDC > > > > High reading +3.5 nVDC > > > > Total Variation 73 nVDC > > > > > > > > So that correlates with my visual observation of 60 nVDC. After an > > > > hour > > > > the room had gone up around 1 degree C. Then I observed -000.00023 > > mVDC. > > > > After another ACAL the reading was again +000.00002 mVDC. This > > particular > > > > meter has a negative tempco as the room temp goes up. > > > > > > > > Obviously do an ACAL before any precision measurements requiring > > low > > > > nanovolts. > > > > > > > > Go to the Keysight website and go to "Technical Support" and choose > > > > "Parts". Then enter in the "Part Number" "03458-66517" which is the > > > > replacement "03458-66507" assembly and you will see the replacement > > part > > > > number on the right hand side. Click on that and you will get the > > > > information about the exchange program and so on. Looks like you can > > just > > > > order this part online and pay for it with a credit card, but you have > > to > > > > create or use an existing login account. > > > > > > > > I needed a new display a few years ago. At that time you could > > order > > > > just the display for around $80. Being extremely good at removing and > > then > > > > inserting and soldering I ordered the part. The problem was that the > > > > spacing from top to bottom of the pins had changed. It went from > > around > > > > 1.3 > > > > inches to around 1.5 inches. So I had to bend the pins to fit my > > display > > > > board and then get something like 72 pins into the holes on the PC > > Board. > > > > It took hours. This change is probably why HP/Agilent/Keysight doesn't > > let > > > > you just get the display anymore but wants you to get the whole PC > > Board > > > > assembly. It did work just fine once installed. > > > > > > > > Hope this helps your decision to keep or not. > > > > > > > > Bill > > > > > > > > > > > > > > > > ----- Original Message ----- > > > > From: "Randy Evans" <randyevans2688@gmail.com> > > > > To: "Discussion of precise voltage measurement" <volt-nuts@febo.com> > > > > Sent: Saturday, August 16, 2014 10:36 PM > > > > Subject: Re: [volt-nuts] RE "new" 3458A > > > > > > > > > > > > > Interesting note. After the room cooled down from about 79F to 73F, > > and > > > > > another ACAL, the meter now reads +000.00035 mVDC, a more reasonable > > > > value, > > > > > although it does bounce around a couple of tenths of a uV. > > > > > > > > > > Maybe that is OK? If so, then the only issue would seem to be the > > > > display > > > > > has some faint pixels, which a new display should fix. > > > > > > > > > > Randy > > > > > > > > > > > > > > > On Sat, Aug 16, 2014 at 9:59 PM, Randy Evans > > <randyevans2688@gmail.com> > > > > > wrote: > > > > > > > > > > > > > > > > > The unit seems to be working so far except for one issue. After > > doing > > > > an > > > > > > ACAL, and making sure the Auto Zero is ON, I short the input leads > > > > with > > > > a > > > > > > copper wire shunt across the inputs and the reading is > > approximately > > > > > > -000.0023 mVDC. That seems rather high. I would expect the unit > > to > > > > short > > > > > > the input leads internally and force a zero reading during the > > ACAL. > > > > > > Anyone have any comments on this reading? > > > > > > > > > > > > Thanks, > > > > > > > > > > > > Randy > > > > > > > > > > > > > > > > > > On Sat, Aug 16, 2014 at 3:37 PM, Richard Moore > > <richiem5683@gmail.com> > > > > > > wrote: > > > > > > > > > > > >> Hi Randy -- sounds like your unit is in cal, based on your > > > > measurements > > > > > >> of DCV and precision 10k resistor. > > > > > >> > > > > > >> Using autocal all is recommended before doing precision > > measurements, > > > > and > > > > > >> I do that if it's been more than a day or two since last use. The > > > > autocal > > > > > >> uses the internal Vref and an internal 10K resistor to do cal on > > > > everything > > > > > >> else, so that tells you what the basic cal procedure is. I just > > got > > my > > > > 3458 > > > > > >> back from Loveland, and that's what they did for me -- warmed it > > up, > > > > then > > > > > >> ran autocal, then measured everything against a Fluke 5700, aided > > by > > > > an > > > > HP > > > > > >> 3325, and another 3458. > > > > > >> > > > > > >> It has been 5 years since I replaced the display board (no > > "exchange" > > > > > >> deal was available then AFAIK, so I don't know what's changed) and > > > > also > > > > the > > > > > >> NVRAM board, which was dead, with one with the Snap-cap RAM chips. > > I > > > > did > > > > > >> those replacements, then sent it home for cal, which was complete, > > > > since > > > > > >> all the RAM was new. Now after 5 years, the unit passed all > > incoming > > > > > >> performance tests and was sent back to me without a cal process of > > any > > > > > >> kind. This tells me that an old, well-aged Vref module is a good > > > > thing. > > > > The > > > > > >> 10VDC test had changed by a bit under 5ppm, or roughly 1ppm/year. > > > > > >> > > > > > >> They have a cal deal -- use code 1.090 -- press them for it -- and > > > > that > > > > > >> saved me 30% off the normal price. I think this deal lasts until > > > > > >> mid-September, so my recent "cal" ended up at just under $400 > > > > including > > > > > >> shipping. I'm not sure the deal is available on new or first-time > > > > cals; > > > > my > > > > > >> unit was in their data bank. > > > > > >> > > > > > >> But this is a long way of saying I don't think you need to send it > > for > > > > > >> cal -- just push Auto Cal and Enter and wait about 10 minutes and > > you > > > > > >> should be good to go. > > > > > >> _______________________________________________ > > > > > >> 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. > > > > > > > _______________________________________________ > > > 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.