[volt-nuts] HP3457

Wed Aug 22 07:57:48 UTC 2012

Any thing that helps to keep the meter at the same temp all the time helps
with stability.

On Wed, Aug 22, 2012 at 12:23 AM, Fred Schneider <pa4tim at gmail.com> wrote:

> So this is normal, hmm, my shop can be over 30 degrees when it is a hot
> summer and 15 degrees in a Cold winter so keeping it powered will not help
> in my case ( i am just an amateur voltnut so climatize my room is no option.
>
> But The service manual describes a test  were you run it at 15 degrees,
> then at 38 degrees and then adjust diodecurrent until you get the best
> tempco. That would imply the thing should not react much on a few degrees.
>
> Would it be an option to ad tempcontrol. The meter itself is a sort of
> uncontrolled oven. If I add a temp sensor and find a way to keep the temp
> steady the meter should stay more stable. In this case cooling would be the
> best option because it gets over 45 - 50 degrees inside the meter. So it
> can heats it self pretty well, The problem is temp follows the oudside
> temp, so if Measure inside temp at for instance 18 or 20 degrees room temp
> and cool it if the inside gets hotter then the inner temp at 20 degrees
> outside, than it must be more stable.
>
> Maybe a piezo element from a coolerbox inside (the piezo is inside, a
> coolrib and fan on theoutside. I experimented with a coolrib on the cabinet
> straight above the transformer, that was allready an improvent. Or some
> aluminum tubes through the cabinet. Open on one side, a box on the other
> side with a fan in it sucking the air through the pipes and cooling the
> inside when needed, or copper tubing where i can solder ribs on. If not
> enough I can pomp water through it and keep the water in an isolated box at
> 30 degrees using an aquarium heater if needed. That would cover 95% of the
> year.
>
> Stupid idea ?
>
>
> Fred PA4TIM
>
> Op 22 aug. 2012 om 03:32 heeft John Phillips <john.phillips0 at gmail.com>
> het volgende geschreven:
>
> > To get better performance form you Solarton keep it a constant Hot
> > temperature all the time. Do not turn it off! Do not let the room
> > temperature fluctuate more than a few degrees. The more stale the better.
> > Cooling in most cases will induce error. If you can keep it at 20C all
> the
> > time go for it but if you are more stable at 28C then 28 is better.
> >
> > The longer you run it the more stable it will get. We do not turn off any
> > of our best meters unless we are moving them or the power gos off.
> >
> >
> > On Tue, Aug 21, 2012 at 4:21 PM, Fred Schneider <pa4tim at gmail.com>
> wrote:
> >
> >> I looked at the DC specs of the 3457 and thats the same as the
> solartron.
> >> I am looking sub uV like the solartron. The 3457 does not have that. So
> I
> >> think, regarding your reactions and the price, i'd better first take a
> look
> >> at the solartron. Modify it a bit ( cooling-ribs on the outside, one on
> top
> >> above the transformer and one on the back where the regulators should
> be (
> >> i'm told, not looked yet) maybe a fan blowing over the ribs.) replace
> the
> >> keylock with a switch ( i have not a good key, it works but not smooth)
> >> then put banana busses instead of the back nr2 input connector on the
> front
> >> and replace the mainsswitch to the front. ( instead of climbing on a
> hair
> >> to reach the switch)
> >>
> >> I printed the service manual of the 7061 and i think I first do the
> tests
> >> ( psu, frequency, input current ect) i also noted my zero problem is
> >> because I shorted both inputs but i need to short the reference and
> front
> >> inputs. That could explain why zero often does not work ( error, zero to
> >> large or something lile that)
> >>
> >> I bought a Keithley 2000 last year, it was comparable to the Fluke 8046
> >> but around 400 euro cheaper. I bought it straight from Keithley
> including
> >> calibration. Besides that I have a keithley 196 that was just calibrated
> >> when I bought it. ( and a 199)
> >>
> >> I was aiming for the holy grale of meters and a 3457 turns out to be a
> >> whole different beast. Someone I know bought a 3456 for 225 euro, fresh
> >> calibrated, that is 6,5 digits too. So i wondered why is a 3457 so much
> >> more expensive.
> >>
> >> But I better wait and save more money in the hope to find one day an
> >> affortable 3458.
> >> One should always keep something to dream about :-)
> >>
> >> Fred
> >>
> >>
> >>
> >>
> >> Fred PA4TIM
> >>
> >> Op 21 aug. 2012 om 22:06 heeft John Phillips <john.phillips0 at gmail.com>
> >> het volgende geschreven:
> >>
> >>> you can put your 3457A into statistics mode and pick up +/- 29,999,999
> >>> counts from the display.
> >>> +/- 2,999,999 counts  is all you can get form the normal /live mode.
> >>>
> >>> On Tue, Aug 21, 2012 at 12:52 PM, J. L. Trantham <jltran at att.net>
> wrote:
> >>>
> >>>> Fred,
> >>>>
> >>>> 700 euro seems a bit high, at least by US standards, for a 3457A.  It
> >> is a
> >>>> good meter and I have one.  Though no longer supported, Agilent will
> >> still
> >>>> calibrate one for $200.22, according to their website.
> >>>>
> >>>> You might want to consider a Fluke 8846A.  I  have seen them sell for
> >> $900
> >>>> new.  I don't have one but it was going to be my next addition until I
> >> got
> >>>> a
> >>>> 3458A.
> >>>>
> >>>> What is the issue with the 7061?
> >>>>
> >>>> Joe
> >>>>
> >>>> -----Original Message-----
> >>>> From: volt-nuts-bounces at febo.com [mailto:volt-nuts-bounces at febo.com]
> On
> >>>> Behalf Of Fred Schneider
> >>>> Sent: Tuesday, August 21, 2012 2:00 PM
> >>>> To: volt-nuts at febo.com
> >>>> Subject: [volt-nuts] HP3457
> >>>>
> >>>> I have a solatron 7061 but i am not very impressed with it. Must I go
> >>>> looking for an alternative or is this 7061 when i gave it a good
> >> checkup /
> >>>> overhaul a good meter ?
> >>>> I am offered a 3457 for 700 euro and the owner, will calibrate it (he
> >> has
> >>>> several calibrtors, standards and a couple of 3458  meters. My
> intuition
> >>>> tells me to trusts him ( and that had never let me down before))
> >>>>
> >>>> But he also told it is only 7,5 digit over hpib, and has 6,5 digit
> >> display.
> >>>>
> >>>> My Keithly 2000 is 6,5 digits and over RS232 i get two digits extra. I
> >> once
> >>>> tried that, but that took me a lot of time to get it more ore less
> >> working,
> >>>> I am not so into computers and afraid I do not get it to work.
> >>>>
> >>>> Is it really better as my ( one year old 2000 ?) and better as my
> >> Solartron
> >>>> can be ?
> >>>> I am afraid a 3458 is outside my budget.
> >>>>
> >>>> Fred
> >>>>
> >>>>
> >>>>
> >>>> Fred PA4TIM
> >>>> _______________________________________________
> >>>> volt-nuts mailing list -- volt-nuts at febo.com To unsubscribe, go to
> >>>> https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
> >>>> and follow the instructions there.
> >>>>
> >>>>
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> >>>>
> >>>
> >>>
> >>>
> >>> --
> >>> John Phillips
> >>> _______________________________________________
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> >>> and follow the instructions there.
> >>
> >> _______________________________________________
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> >>
> >
> >
> >
> > --
> > John Phillips
> > _______________________________________________
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-- 
John Phillips