Randy,

Sorry for the two graphs being at different scales so just be sure to readjust 
your reference. I like to think in PPM terms so the first graph is +/- 5 PPM 
for the whole gray plot area while the second is +/- 1 PPM. The most extreme 
outliers on the first graph is +0.3 to -0.5 PPM so that would be <10.0 uV. The 
winter graph is +0.1 to -0.9 PPM and would be 10.0 uV. All referenced around 
10.0 V.

Don

-----Original Message-----
From: volt-nuts [mailto:volt-nuts-boun...@febo.com] On Behalf Of Randy Evans
Sent: Wednesday, August 27, 2014 10:50 AM
To: Discussion of precise voltage measurement
Subject: Re: [volt-nuts] 732A and Prologix received

Don,

If I am reading your charts correctly, it looks like your system is cycling 
over an 7 uV range over several days in summer, similar to what I am seeing.  I 
don't have air conditioning (Northern California) so I do get some pretty good 
temperature variations from day to night, but less inside the house.

I need to figure out how to share files in Dropbox since I don't have my own 
web site.  Good idea.

thanks,

Randy



On Wed, Aug 27, 2014 at 7:40 AM, Don@True-Cal <truecalservi...@gmail.com>
wrote:

> I have included a link to an ~30-hour measurement run that I 
> consistently do that should give you some idea of expected measurement drift 
> over time.
> Virtually all of the measurement drift is due to the 3458A internal 
> temperature differences around the 7V reference caused by ambient 
> temperature change. The drift associated with the 732A is probably 
> about 2-magnitudes less at this ambient temp drift. In my situation, 
> the inferred ambient temperature is cycling with the home 
> air-conditioning. Note the initial calibration temperatures as well as 
> the ACal temperatures and where the 3458A is measuring exactly 10V 
> relative to those temperatures. My primary 732A has been powered 
> without loss for 4 years and >5 years before that. The 3458A is 
> Agilent (Loveland) Cal'ed yearly and is powered 24-7-365 except for 
> the occasional mains power loss. The graphical measurements is using a 
> homegrown Agilent VEE program. It is very helpful if not essential to get an 
> HPIB interface setup so you can do long term graphical analysis.
>
> The other link was done in winter time when the lab a few degrees cooler.
>
>
> https://www.dropbox.com/s/8je482i3r0belqn/732A%20gold%20%26%203458A%20
> gold%2032-hour%20Ref%20Test%208-21-2014.pdf?dl=0
>
>
> https://www.dropbox.com/s/xv3l9py7tx6hyh7/HP%20732A%20gold%20%26%20345
> 8A%20gold%207-day%2010.0v%20Ref%20Test.pdf?dl=0
>
> I hope these Dropbox links work internationally - I'm new to using 
> this sharing method.
>
> Don Johnson
>
> -----Original Message-----
> From: volt-nuts [mailto:volt-nuts-boun...@febo.com] On Behalf Of 
> acb...@gmx.de
> Sent: Wednesday, August 27, 2014 8:42 AM
> To: Discussion of precise voltage measurement
> Subject: Re: [volt-nuts] 732A and Prologix received
>
> well, what you do is to measure the stability of the 3458a. 1ppm drift 
> though sounds much as overall short term average variation if your 
> temperature is stable and your 3458a is always on. probably the temp 
> is not stable, and that is what you see, amongst potentially some 
> other smaller drifts like emf. before every cycle you should do an 
> acal dcv, if you still see 10uv +/- drifts that then seems too much. 
> (one thing I need to add is that one of my 3458a, not yet modified to 
> have lower reference temperature, has drifts when switched on and off. 
> that is not so much the case with modified reference. but my 
> assumption re the above is that your meter is always on, as I said) 
> 732a references et al do have small short term drifts, you can 
> determine them with a josephson element (these guys told me), but the 732a is 
> certainly very stable short term compared to a 3458a.
> my 732a e.g. has a drift of 0.2ppm per year.
>
>
> > Gesendet: Mittwoch, 27. August 2014 um 14:36 Uhr
> > Von: "Randy Evans" <randyevans2...@gmail.com>
> > An: "Discussion of precise voltage measurement" <volt-nuts@febo.com>
> > Betreff: Re: [volt-nuts] 732A and Prologix received
> >
> > I forgot to mention that I reduced the number of measurements to 100 
> > per set since I wasn't seeing much difference in the variance 
> > between 100 and
> > 1000 measurements and the 1000 measurement per set takes too long.
> >
> > Randy
> >
> >
> > On Wed, Aug 27, 2014 at 5:13 AM, Randy Evans 
> > <randyevans2...@gmail.com>
> > wrote:
> >
> > > I am doing multiple 100 measurements simply to characterize the
> stability
> > > of the 3458A and 732A units I just bought.  After about 10 
> > > measurement
> sets
> > > over 2 days I am seeing a variance of about .5 uV for the 10V 
> > > output,
> or
> > > 0.05 ppm.  However, the mean varies over a range of 10 uV, or 1 ppm.
> Does
> > > that sound reasonable/
> > >
> > > Randy
> > >
> > >
> > > On Tue, Aug 26, 2014 at 5:41 PM, <acb...@gmx.de> wrote:
> > >
> > >> hi randy,
> > >>
> > >> just for curiosity, why doing 100 measurements at nplc 1000. is 
> > >> this
> to
> > >> sample a changing value?
> > >> when i am doing 10 measurements from a stable signal at nplc 100 
> > >> (only there many subsequent measuremnts with statistics make 
> > >> sense) I am
> already
> > >> getting a stanard deviation below 0.1ppm.
> > >> in a 30 minute test cycle, i would also be concerned about drifts
> (acal)
> > >> unless the amb. temperature is really very stable (half a degree
> already
> > >> adds about 0.25ppm at 10v)
> > >>
> > >> thanks
> > >>
> > >>
> > >>
> > >>
> > >> > Gesendet: Dienstag, 26. August 2014 um 04:23 Uhr
> > >> > Von: "Randy Evans" <randyevans2...@gmail.com>
> > >> > An: "Discussion of precise voltage measurement" 
> > >> > <volt-nuts@febo.com
> >
> > >> > Betreff: Re: [volt-nuts] 732A and Prologix received
> > >> >
> > >> > Is there any way to tell when the function key routine is
> complete?  In
> > >> the
> > >> > case of taking multiple readings using the DEFKEY and MATH
> function, I
> > >> > don't see any indication when the routine is complete.  In one
> > >> particular
> > >> > case, I am taking a 100 readings with NLPC set for 1000 so its 
> > >> > a
> long
> > >> while
> > >> > before it's complete, but i have to guess when it's done.
> > >> >
> > >> > Thanks,
> > >> >
> > >> > Randy
> > >> >
> > >> >
> > >> > On Sun, Aug 24, 2014 at 6:04 PM, Randy Evans <
> randyevans2...@gmail.com>
> > >> > wrote:
> > >> >
> > >> > > Bill,
> > >> > >
> > >> > > I am trying to figure out the MATH function without much
> success.  I
> > >> input
> > >> > > the sequence you said (I looked up the instructions to 
> > >> > > understand
> > >> what you
> > >> > > did - seems logical), BLUE DEFKEY BLUE F1 MATH 14;NRDGS 
> > >> > > 40;TRIG
> > >> 4;TRIG; and
> > >> > > it shows up on the display when I input BLUE F1.  I hit ENTER 
> > >> > > and
> it
> > >> takes
> > >> > > the 40 measurements and the MATH symbol shows on the display
> during
> > >> the
> > >> > > measurements.  After the SMPL symbol no longer blinks I hit 
> > >> > > MATH 2
> > >> and I
> > >> > > get a MATH ERR symbol on the display.  I tried it a couple of
> times
> > >> and the
> > >> > > same result so I am doing something wrong.  Is there a better
> source
> > >> for
> > >> > > explaining how to do front panel masurements than the User 
> > >> > > Guide,
> > >> which
> > >> > > seems oriented at programming automatic rather than manual
> > >> measurements.
> > >> > >
> > >> > > Randy
> > >> > >
> > >> > >
> > >> > >
> > >> > > On Sun, Aug 24, 2014 at 4:46 PM, Bill Gold 
> > >> > > <wpgold3...@att.net>
> > >> wrote:
> > >> > >
> > >> > >> Randy:
> > >> > >>
> > >> > >>     The MATH function is accessible from the keypad.  I 
> > >> > >> don't
> have
> > >> an IEEE
> > >> > >> interface right now that works.  You can also program the 
> > >> > >> numeric
> > >> keypad
> > >> > >> keys to have preprogrammed functions.  DEFKEY
> > >> > >>
> > >> > >>     I have made my own "low thermal" measurement leads from
> Pomona
> > >> #4892
> > >> > >> banana plugs and Belden #9272 wire.  Why 9272, because it 
> > >> > >> was
> handy
> > >> at the
> > >> > >> time.  It is tin plated copper, shielded twisted pair 20 ga.  
> > >> > >> I
> have
> > >> plans
> > >> > >> to do custom cables with 16 ga. bare copper wire that I will
> twist
> > >> and
> > >> > >> then
> > >> > >> put a braided shield over it.  I simply cannot find what I 
> > >> > >> want
> so I
> > >> will
> > >> > >> build my own cable.  I have done something like this before 
> > >> > >> and
> it
> > >> worked
> > >> > >> fine.  When I get a "round toit".
> > >> > >>
> > >> > >>     I have 6 ea. Pomona 1756-48 spade lug low thermal leads 
> > >> > >> that
> I
> > >> have
> > >> > >> used
> > >> > >> in the past to verify my homemade "low thermal" leads as
> described
> > >> above.
> > >> > >> Frankly I cannot see any difference between using the 1756 
> > >> > >> cables
> > >> and my
> > >> > >> homemade cables once I give them a few minutes for the 
> > >> > >> thermals
> to go
> > >> > >> away.
> > >> > >> As far as I can tell and measure the differences, if any, 
> > >> > >> are
> below
> > >> 0.1
> > >> > >> ppm
> > >> > >> at 10 volts.
> > >> > >>
> > >> > >>     Since the 10 volt, 1.0 volt and 1.018 volt outputs on 
> > >> > >> the
> 732A
> > >> are all
> > >> > >> adjustable you may be seeing a misadjusted 1 volt from the
> 732A.  As
> > >> far
> > >> > >> as
> > >> > >> the instability of the readings it is hard to determine 
> > >> > >> which is
> > >> causing
> > >> > >> the
> > >> > >> problem.  I have programed (DEFKEY) a numeric keypad key #1 
> > >> > >> with
> the
> > >> > >> following code.  "MATH 14;NRDGS 40;TRIG 4;TRIG ;"   So what this
> > >> does is
> > >> > >> set
> > >> > >> the MATH to "Statistics" (store high reading/low reading/ 
> > >> > >> and
> mean
> > >> of the
> > >> > >> readings) in the registers, the number of readings to "40", 
> > >> > >> the
> > >> trigger to
> > >> > >> "hold" (which keeps the meter from triggering until I press
> "ENTER"
> > >> and
> > >> > >> then
> > >> > >> trigger the sequence of 40 readings when I push the "ENTER"
> button.
> > >> You
> > >> > >> can
> > >> > >> do all of this manually from the keypads but since I use 
> > >> > >> this
> > >> sequence a
> > >> > >> lot
> > >> > >> I have preprogrammed it.  This is after I set digits to "8" 
> > >> > >> and
> PLC
> > >> to
> > >> > >> 100.
> > >> > >> Once those 40 readings are finished then you can access the
> various
> > >> MATH
> > >> > >> statistic registers, using the menu, by entering "MATH" and 
> > >> > >> then
> a 2
> > >> for
> > >> > >> low, a 4 for mean, and 13 for high.  Of course you could do 
> > >> > >> all
> of
> > >> this
> > >> > >> through the IEEE also.  The 3458A has a very rich set of
> measurement
> > >> > >> commands.  I am still learning all of them.  It depends upon
> what I
> > >> am
> > >> > >> trying to accomplish.
> > >> > >>
> > >> > >>     Since the 1.018 and 1.0 volt outputs are passive and 
> > >> > >> derived
> from
> > >> > >> resistive dividers from the 10 volt, I don't see how they 
> > >> > >> could
> > >> contribute
> > >> > >> to the varying readings you are measuring.  I think I would 
> > >> > >> put a
> > >> short on
> > >> > >> the input of the 3458A and manually set the range to 1 volt 
> > >> > >> and
> then
> > >> > >> observe
> > >> > >> the variations that way without the 732A involved.  When I 
> > >> > >> do
> this I
> > >> see a
> > >> > >> variation from low reading to high reading of 0.125 uVolts 
> > >> > >> and
> then
> > >> > >> another
> > >> > >> 40 I get 0.155 uVolts.  This is without the GUARD connected 
> > >> > >> to
> the
> > >> low
> > >> > >> side
> > >> > >> of the measurment terminals, GUARD connected doesn't seem to
> affect
> > >> the
> > >> > >> readings.  So that is the base noise of the 3458A without 
> > >> > >> the
> 732A,
> > >> > >> somewhere below .2uVolts.  When hooked up to the 732A 1.0 
> > >> > >> volt
> > >> output I
> > >> > >> got
> > >> > >> a variation of 0.159 uVolts using the same 40 reading method
> above.
> > >> I
> > >> > >> would
> > >> > >> use this to determine where your problem might exist.  Just
> having
> > >> the
> > >> > >> meter
> > >> > >> input shorted will point you in the right direction.  Meter,
> cables
> > >> or
> > >> > >> 732A.
> > >> > >>
> > >> > >>     Sorry for the long dissertation.  Friends get mad at me 
> > >> > >> for
> > >> being so
> > >> > >> detailed sometimes.
> > >> > >>
> > >> > >> Bill
> > >> > >>
> > >> > >> ----- Original Message -----
> > >> > >> From: "Randy Evans" <randyevans2...@gmail.com>
> > >> > >> To: "Discussion of precise voltage measurement" <
> volt-nuts@febo.com>
> > >> > >> Sent: Sunday, August 24, 2014 7:22 AM
> > >> > >> Subject: Re: [volt-nuts] 732A and Prologix received
> > >> > >>
> > >> > >>
> > >> > >> > Bill,
> > >> > >> >
> > >> > >> > I have convinced myself that the problem I an seeing is 
> > >> > >> > due to
> > >> thermals.
> > >> > >> >  If I move the cables (with gold-plated banana plugs) 
> > >> > >> > using a
> small
> > >> > >> towel
> > >> > >> > rather than letting my hand touch the plugs, it is much 
> > >> > >> > more
> > >> stable.
> > >> > >> If I
> > >> > >> > then hold the banana plug with my hand after the reading 
> > >> > >> > has
> > >> stabilized,
> > >> > >> > the reading drifts rapidly upward.  I am trying to check 
> > >> > >> > the
> > >> stability
> > >> > >> of
> > >> > >> > the reading but I haven't figured out the MATH function 
> > >> > >> > yet.  I
> > >> assume
> > >> > >> this
> > >> > >> > is a programmed function using GPIB only?
> > >> > >> >
> > >> > >> > The stability I am seeing by manually recording readings 
> > >> > >> > (using
> > >> NLPC of
> > >> > >> 100
> > >> > >> > and 1000) is much greater than what you are measuring on 
> > >> > >> > your
> > >> system.
> > >> > >> Not
> > >> > >> > sure how to ascertain if it's the 3458A or the 732.  The 
> > >> > >> > value
> of
> > >> the
> > >> > >> > readings are very different between the two - the 3458 
> > >> > >> > reads
> about
> > >> 50 uV
> > >> > >> > high on the 10 V output and about 12 uV low on the 1V output.
> > >> Rather
> > >> > >> large
> > >> > >> > differences (this is after an ACAL).  I need to find some
> better
> > >> cables
> > >> > >> to
> > >> > >> > make sure the errors are not due to thermals again.
> > >> > >> >
> > >> > >> > Randy
> > >> > >> >
> > >> > >> >
> > >> > >> > On Sat, Aug 23, 2014 at 10:21 AM, Bill Gold <
> wpgold3...@att.net>
> > >> wrote:
> > >> > >> >
> > >> > >> > > Randy:
> > >> > >> > >
> > >> > >> > >     I get 6 volt 4 amp/hr (or 4.5 amp/hr) batteries and 
> > >> > >> > > they
> > >> will fit
> > >> > >> > > perfect.  Power Sonic PS-640, Genesis NP4-6, Panasonic
> > >> LC-R064R5C and
> > >> > >> > > others
> > >> > >> > > that are in this size and package.  Order from one of 
> > >> > >> > > the
> usual
> > >> > >> electronics
> > >> > >> > > distributors like Allied, Mouser, Digikey.  This is a 
> > >> > >> > > very
> common
> > >> > >> battery
> > >> > >> > > as
> > >> > >> > > it is used in a lot of "EXIT" signs so they are lighted 
> > >> > >> > > when
> the
> > >> power
> > >> > >> goes
> > >> > >> > > out.  I don't see how the 12V 7AH will fit as they are 
> > >> > >> > > too
> > >> large.  I
> > >> > >> guess
> > >> > >> > > you could use a 12V 5AH (PS1250) as it is the same size 
> > >> > >> > > as 2
> x 6
> > >> volt
> > >> > >> 4
> > >> > >> AH
> > >> > >> > > but the terminals are in the wrong place so you will 
> > >> > >> > > have to
> > >> "nibble"
> > >> > >> out
> > >> > >> > > the aluminum plate that holds them in the 732A battery pack.
> > >> You have
> > >> > >> to
> > >> > >> > > be
> > >> > >> > > careful if you use the 12v 5AH as you will have 4 extra
> battery
> > >> > >> connection
> > >> > >> > > leads to deal with and connect correctly.  I would stick 
> > >> > >> > > with
> > >> the 6V
> > >> > >> 4AH.
> > >> > >> > > New batteries will last around 12 to 14 hours before the
> "CAL"
> > >> light
> > >> > >> goes
> > >> > >> > > out when AC power is not applied.  So shipping to Cal 
> > >> > >> > > Lab
> can be
> > >> a
> > >> > >> problem
> > >> > >> > > if it is a distance away, or you have to use a shipper 
> > >> > >> > > like
> UPS
> > >> or
> > >> > >> FEDEX
> > >> > >> > > and
> > >> > >> > > you ship the night before and then use their "Morning
> delivery"
> > >> and
> > >> > >> the
> > >> > >> Cal
> > >> > >> > > Lab is expecting your 732A.  Same on the way back to 
> > >> > >> > > you.  Of
> > >> course
> > >> > >> you
> > >> > >> > > could always strap another battery on the 732A and hook 
> > >> > >> > > it
> up to
> > >> the
> > >> > >> "ext
> > >> > >> > > power" plug to last longer.  I have seen it done.  The 
> > >> > >> > > issue
> is
> > >> to get
> > >> > >> the
> > >> > >> > > Cal Lab to charge the extra battery before they ship the 
> > >> > >> > > 732A
> > >> back to
> > >> > >> you.
> > >> > >> > >
> > >> > >> > >     When you remove and work on the battery pack always 
> > >> > >> > > have
> the
> > >> AC
> > >> > >> power
> > >> > >> > > plugged in.  The "CAL" led will stay on because the 18.6 
> > >> > >> > > v
> > >> regulated
> > >> > >> supply
> > >> > >> > > is working.
> > >> > >> > >
> > >> > >> > >     The "CAL" light is to indicate that power has not 
> > >> > >> > > been
> lost
> > >> to the
> > >> > >> > > Reference Amp or other associated circuits.  When the 
> > >> > >> > > raw
> supply
> > >> > >> (battery)
> > >> > >> > > voltage drops below about 21 volts the "CAL" light will 
> > >> > >> > > go
> out.
> > >> Below
> > >> > >> that
> > >> > >> > > voltage the heater circuits will not work correctly and 
> > >> > >> > > the
> 18.6
> > >> volt
> > >> > >> > > regulated supply will not regulate.  The requirement is 
> > >> > >> > > that
> the
> > >> > >> Reference
> > >> > >> > > Amp be kept "alive" at all times to maintain the output
> voltage
> > >> that
> > >> > >> was
> > >> > >> > > measured at the time of the most recent Calibration or
> > >> Certification.
> > >> > >> When
> > >> > >> > > the semiconductor junctions are unbiased and cool off 
> > >> > >> > > when
> power
> > >> is
> > >> > >> lost,
> > >> > >> > > and then power is restored the result will be a 
> > >> > >> > > different 10
> > >> volts
> > >> > >> than
> > >> > >> > > before the power failure.  My experience is that after 
> > >> > >> > > all
> of the
> > >> > >> years
> > >> > >> > > that
> > >> > >> > > these units have been powered up, this won't happen and 
> > >> > >> > > when
> > >> power is
> > >> > >> lost
> > >> > >> > > and then restored, even months later, the 732A will come
> back to
> > >> > >> almost
> > >> > >> > > exactly the same 10 volts as when they lost power, 
> > >> > >> > > usually
> with
> > >> in 0.2
> > >> > >> PPM
> > >> > >> > > after 24 hours of "warm up".
> > >> > >> > >
> > >> > >> > >     What type of hookup leads are you using when 
> > >> > >> > > measuring
> the 1
> > >> volt
> > >> > >> > > output?  What is the PLC set to?  I always use 100 PLC 
> > >> > >> > > to
> measure
> > >> > >> this.
> > >> > >> If
> > >> > >> > > you don't have "low thermal" connection leads you can
> experience
> > >> uV
> > >> > >> changes
> > >> > >> > > for a minute or more after plugging in the leads due to 
> > >> > >> > > the
> > >> "thermals"
> > >> > >> > > generated because of the difference in temperature 
> > >> > >> > > between
> the
> > >> banana
> > >> > >> jacks
> > >> > >> > > on the 732A and the banana plugs of the leads.  I have 
> > >> > >> > > found
> > >> that even
> > >> > >> just
> > >> > >> > > plugging in the lead will generate a thermal difference
> because
> > >> of
> > >> > >> > > difference of temps and some heating due to the physical 
> > >> > >> > > act
> of
> > >> just
> > >> > >> > > inserting the plug because of friction between the jack 
> > >> > >> > > and
> plug
> > >> (my
> > >> > >> theory
> > >> > >> > > at any rate).  You have to allow at least a minute or 
> > >> > >> > > more
> before
> > >> > >> being
> > >> > >> > > able
> > >> > >> > > to make a measurement after plugging in the leads.  I 
> > >> > >> > > just
> > >> measured
> > >> > >> the
> > >> > >> > > variation of the 1 volt output of my 732A and using my 
> > >> > >> > > 3458A
> and
> > >> I
> > >> > >> got a
> > >> > >> > > total difference of  0.159 uV over 40 measurements using 
> > >> > >> > > 100
> PLC
> > >> on
> > >> > >> the
> > >> > >> 1
> > >> > >> > > volt range of the 3458A.  Using the MATH function and 
> > >> > >> > > all of
> the
> > >> data
> > >> > >> you
> > >> > >> > > can collect.  That was after waiting for several minutes
> after
> > >> > >> plugging
> > >> > >> in
> > >> > >> > > the leads.
> > >> > >> > >
> > >> > >> > >     I hope all of this helps.
> > >> > >> > >
> > >> > >> > > Bill
> > >> > >> > >
> > >> > >> > >
> > >> > >> > >
> > >> > >> > > ----- Original Message -----
> > >> > >> > > From: "Randy Evans" <randyevans2...@gmail.com>
> > >> > >> > > To: "Discussion of precise voltage measurement" <
> > >> volt-nuts@febo.com>
> > >> > >> > > Sent: Friday, August 22, 2014 9:03 PM
> > >> > >> > > Subject: Re: [volt-nuts] 732A and Prologix received
> > >> > >> > >
> > >> > >> > >
> > >> > >> > > > Todd,
> > >> > >> > > >
> > >> > >> > > > Thanks for the info.  I have several Panasonic 12V 7 
> > >> > >> > > > AH
> > >> batteries
> > >> > >> that
> > >> > >> I
> > >> > >> > > > keep topped off and they have very low current draw 
> > >> > >> > > > (~2 to
> 3
> > >> mA at
> > >> > >> 13.5
> > >> > >> > > > VDC) when charged and at their float voltage, so I am
> pretty
> > >> sure
> > >> > >> they
> > >> > >> > > are
> > >> > >> > > > in good condition.  I will look at getting those in 
> > >> > >> > > > the
> units
> > >> after
> > >> > >> I
> > >> > >> > > > ascertain the condition of the 732.
> > >> > >> > > >
> > >> > >> > > > So now I have a what appears to be a functioning 3458A 
> > >> > >> > > > and
> a
> > >> 732A
> > >> > >> but
> > >> > >> > > they
> > >> > >> > > > slightly disagree.  I am like the man with two watches 
> > >> > >> > > > that
> > >> disagree
> > >> > >> on
> > >> > >> > > the
> > >> > >> > > > time  - which is correct?  For the moment, i am only
> concerned
> > >> with
> > >> > >> > > > stability.  The need for absolute accuracy will come later.
> > >> > >> > > >
> > >> > >> > > > Randy
> > >> > >> > > >
> > >> > >> > > >
> > >> > >> > > > On Fri, Aug 22, 2014 at 8:06 PM, Todd Micallef <
> > >> tmical...@gmail.com
> > >> > >> >
> > >> > >> > > wrote:
> > >> > >> > > >
> > >> > >> > > > > Randy,
> > >> > >> > > > >
> > >> > >> > > > > You have two possible choices. It can be configured 
> > >> > >> > > > > with
> 4 x
> > >> 6v
> > >> > >> 4Ah
> > >> > >> > > > > batteries or 2 x 12v 7Ah batteries. Hopefully the
> previous
> > >> owner
> > >> > >> has
> > >> > >> > > > > modified the battery pack already. A couple of mine
> needed a
> > >> > >> nibbler
> > >> > >> > > tool
> > >> > >> > > > > to remove enough of the aluminum cover that fits 
> > >> > >> > > > > over the
> > >> tops of
> > >> > >> the
> > >> > >> > > > > batteries. The original cover will short out to the
> battery
> > >> tabs
> > >> > >> > > regardless
> > >> > >> > > > > of the battery configuration if this is not done.
> > >> > >> > > > >
> > >> > >> > > > > You can find larger capacity batteries that will 
> > >> > >> > > > > give you
> > >> slightly
> > >> > >> more
> > >> > >> > > > > battery life. I lost a couple sets of mail-order
> batteries
> > >> after a
> > >> > >> few
> > >> > >> > > > > extended outages. I would recommend going with 
> > >> > >> > > > > locally
> bought
> > >> > >> batteries
> > >> > >> > > > > instead of the cheaper mail order. My local 
> > >> > >> > > > > Batteries
> Plus
> > >> will
> > >> > >> > > typically
> > >> > >> > > > > have some warranty if I remember correctly. Moving
> forward I
> > >> will
> > >> > >> only
> > >> > >> > > use
> > >> > >> > > > > 2 12v batteries and pre-charge them on a battery 
> > >> > >> > > > > charger
> to
> > >> > >> equalize
> > >> > >> > > them
> > >> > >> > > > > before putting them in the 732A. I think the cheap
> batteries
> > >> did
> > >> > >> not
> > >> > >> > > > > discharge equally, and would not recover when power 
> > >> > >> > > > > was
> > >> applied.
> > >> > >> > > > >
> > >> > >> > > > > Inspect the back plane for damaged traces and look 
> > >> > >> > > > > at the
> > >> > >> capacitors. I
> > >> > >> > > had
> > >> > >> > > > > a few that looked questionable. So far, I have 
> > >> > >> > > > > replaced
> all
> > >> the
> > >> > >> big
> > >> > >> > > caps
> > >> > >> > > on
> > >> > >> > > > > the pre-regulator and regulator boards. My feeling 
> > >> > >> > > > > is
> that
> > >> once
> > >> > >> these
> > >> > >> > > go
> > >> > >> > > > > online, they should run as long as possible between
> repairs.
> > >> > >> > > > >
> > >> > >> > > > > The battery charger circuit may need adjusting. I 
> > >> > >> > > > > tweaked
> > >> mine and
> > >> > >> it
> > >> > >> > > > > seemed to work fine.
> > >> > >> > > > >
> > >> > >> > > > > Todd
> > >> > >> > > > >
> > >> > >> > > > >
> > >> > >> > > > > On Fri, Aug 22, 2014 at 10:42 PM, Randy Evans <
> > >> > >> > > randyevans2...@gmail.com>
> > >> > >> > > > > wrote:
> > >> > >> > > > >
> > >> > >> > > > > > I received my Fluke 732A today.  Just powered it 
> > >> > >> > > > > > up
> but it
> > >> needs
> > >> > >> new
> > >> > >> > > > > > batteries.  Any suggestions for sources (I haven't
> opened
> > >> up the
> > >> > >> unit
> > >> > >> > > > > yet -
> > >> > >> > > > > > I want to make sure it works before doing that).  
> > >> > >> > > > > > Also
> > >> received
> > >> > >> the
> > >> > >> > > > > > ProLogix USB-GPIB adapter.  I plan on using Mark Sims'
> CAL
> > >> ran
> > >> > >> data
> > >> > >> > > > > dumper
> > >> > >> > > > > > program to get the CAL data from my 3458A.  Should 
> > >> > >> > > > > > be a
> > >> busy
> > >> > >> weekend.
> > >> > >> > > > > >
> > >> > >> > > > > > Randy
> > >> > >> > > > > > _______________________________________________
> > >> > >> > > > > > 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-n
> > >> > >> > > > > uts and follow the instructions there.
> > >> > >> > > > >
> > >> > >> > > > _______________________________________________
> > >> > >> > > > volt-nuts mailing list -- volt-nuts@febo.com To 
> > >> > >> > > > unsubscribe, go to
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> > >> > >> > >
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> > >> > >
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