[volt-nuts] RE "new" 3458A

Bill Gold wpgold3637 at att.net
Sun Aug 17 15:54:42 EDT 2014 

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 at gmail.com>
To: "Discussion of precise voltage measurement" <volt-nuts at 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 at 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 at gmail.com>
> > To: "Discussion of precise voltage measurement" <volt-nuts at 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 at 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 at gmail.com>
> > > > To: "Discussion of precise voltage measurement" <volt-nuts at 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 at 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 at 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.
> > > > > >> _______________________________________________
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> > > > > >>
> > > > > >
> > > > > >
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