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 <wpgold3...@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" <randyevans2...@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 <wpgold3...@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" <randyevans2...@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 > <randyevans2...@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 > <richiem5...@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.
