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Wow, lots of replies all of a sudden. I'm already prepping the wife for
the $200 + price tag of calibration. Funny how when I was single I would
have about $800 in cash in my wallet at all times and now I beg for 20
bucks, Hmm. Sad part is I make about 4 times the money. In any event
I've not received to much feedback on the "Self Test OK" message the
seller had posted. Any comments? I'm too much of a skeptic when it comes
to eBay purchases. It's just a convenient place to purchase such goods.
Any feedback would be appreciated as to possible pitfalls regarding this
device. I like to prep for issues rather then build myself up for
failure. What do they say...it's better to be pleasantly surprised then
let down.

Thanks,

Jeff

On 12/29/2012 5:40 PM, J. L. Trantham wrote:

According to the manual, there are only two 'adjustments' that can be made
on a 3457A, Input Offset Amplifier adjustment and AC Converter Frequency
Response, both needed only if there is a 'HARDWARE ERR' failure message
after 'TEST' is selected and then only if it is a specific 'AUXERR' or
16 or
256 is seen. Otherwise, all the calibrations are done from the front panel
with specific inputs from the front panel.

The CALNUM? is incremented by 'several digits' with a 'complete
calibration', one for each calibration point entered, per the manual.
Interestingly, when I sent my two 3458A's to Agilent for calibration, the
CALNUM incremented by only 1. However, when I calibrated one of them
before
sending it to Agilent, (since I lost the data in the DALLAS CALRAM
chip that
I was removing) the CALNUM went from 1 to something like 34 or
something. I
don't recall. It seems that if you have the appropriate software to
run the
complete calibration protocol, it only increments by '1' instead of by all
the data points entered. Such software exists for the 3457A but I have
never seen it available 'on theBay'. I suspect Agilent would have that
software and equipment to do that calibration and, thus, an Agilent
calibration may only increment the CALNUM? by 1.

When getting an Agilent calibration of the 3458A, you get 'As
Received' and
'As Completed' data. Very helpful to me in that the only two points my
'House CAL' of the one 3458A failed were the two 'midrange' AC Voltage
values. All else 'PASSED'.

I agree with Dave. If it's HP/Agilent, I prefer Agilent to do the CAL. If
it's Solartron, I prefer AMETEK (Solartron), etc.

I believe that having some 'basic' professionally calibrated instruments
(DMM's, Noise Sources, Power Sensors, Frequency Standards (unless you
have a
GPSDO, CS Standard, etc.) etc.), that you can then use as 'transfer
standards' to do your own 'in house' calibration of other instruments, is
very important if you want to set up a reliable workshop.

Of course, you will also need a 'stable' source of the various signals
that
you will use to be 'measured' by the various 'DUT's', such as resistance,
voltage, current, frequency, etc. The 3458A is relatively easy to
calibrate, requiring only 10.000000 VDC, 10000.000 ohms, and some AC
voltage
at various frequencies, IIRC. I have never CAL'd a 3457A but the 3478A
is a
multi-step process.

This whole thing can become very 'addictive'. Be careful.

Joe

-----Original Message-----
From: hp_agilent_equipment@...
<mailto:hp_agilent_equipment%40yahoogroups.com>
[mailto:hp_agilent_equipment@...
<mailto:hp_agilent_equipment%40yahoogroups.com>] On Behalf Of David Kirkby
Sent: Saturday, December 29, 2012 5:53 PM
To: hp_agilent_equipment@...
<mailto:hp_agilent_equipment%40yahoogroups.com>
Subject: Re: [hp_agilent_equipment] 3457a on the way

On 29 December 2012 20:01, Jeff Machesky <jeff@...
<mailto:jeff%40codebest.com>
<mailto:jeff%40codebest.com> > wrote:

Thanks Dave, I actually have watched those videos. Bit drawn out like
most of his videos..but still good. Too much detail is not always a bad
thing.

I thought the bit showing the noise on the DVM was a bit silly when it
was connected to a DC power supply.

As for the 3457A, if it works I plan on getting it calibrated by Agilent
within the year. From what I understand it's about a $200 US investment.
The meter was last calibrated in '98, so I'll be curious to see how
accurate it is when I get it.

I think the calibration service you chose might dictate whether you
get data about the condition when sent.

When I send mine in for cal, I'd like to know what was out and by how
much. But I'm not going to pay extra for a calibration service that
provides that. As far as I'm concerned, if Agilent calibrate it, then
it is OK. For me personally, it makes no difference whatsoever if it
has ISO, NIST or whatever calibration. But I'd prefer Agilent to
someone else.

I have calibration certificate here for an Agilent VNA calibration
kit. It was done by a calibration house in the USA. But from what I
can gather from reading the documentation, the equipment to calibrate
them is not available commerically. So it makes me wonder how a lab
can calibrate a cal kit, when the equipment to do it can't be bought.

I suspect there is a fairly cosy realationship between some test
equipment dealers and calibration facilities.

I plan on purchasing some
voltage references from the well known site as a basic test of the
3457A. I may even calibrate it based on those references if it's way out
and later getting it NIST traceable calibrated.

I don't know if there are pots in there you can adjust with a trimmer,
or if it is all done electronically. You might find it is impossible
to calibrate yourself.

I never had any reason to look inside mine.

Dave

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