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Steve, Jeff, and all,

According to the manual, the 'New Main Controller' was installed starting at
SN 2538A02954 and later. The Assembly Number, 03457-665xx, etc., is under
the power transformer and difficult to see but there. Also, regarding the
'new' battery and 'new' resistors, the manual states 'the new parts are on
assembly A11, ERC no. 2850 and greater' which I interpret to mean SN
2850Axxxxx and greater.

The 'New Main Controller' is easy to identify by just looking at where the
battery is located. Looking from the front of the meter, with the top cover
off and the 'shield' over the main controller off, the 'old' controller had
the battery to the left side of the board, near the left side of the meter,
about half way back from the front while the 'new' main controller has the
battery on the right side of the board, near the center of the meter, about
one fourth of the way back from the front.

So, if I am correct, my SAFT LX-1634 3.0 V battery represents the 'old' 2.9
volt battery although my battery does not state what the chemistry of the
battery is. Therefore, if I can find an exact replacement of the battery,
chemistry and all, I would prefer to just replace the battery rather than
place a new battery and resistors.

Also, the PCB is manufactured so as to provide mounting for a battery with
one positive and one negative pin as well as a battery with one positive and
two negative pins. Therefore, there may be some other options.

Has anyone found any information specifically about the SAFT LX-1634
battery?

Interestingly, the same SAFT LX-1634 battery is used in the 3478A. I
replaced the 3478A battery with a BR-2/3A several months ago with no
detectable problems so far but the battery backup circuitry is much simpler
than the 3457A. Also, of note, the BR-2/3A reads 3.397 VDC.

As best I can tell, the only role for R644 and R645 is during the Power On
Reset and the Low Power Reset. It would appear that the Low Power Reset is
the only issue of concern. The 'old' components set a level of about 2.99
VDC at the + input of U636A while the 'new' components set a level of about
3.46 VDC at the + input of U636A when the UNREG +5 VDC supply drops to 7
VDC. If no changes in resistors were made, the same 3.46 VDC would occur
when the UNREG +5 VDC supply dropped to about 8.1 VDC. I measure 11.18 VDC
on my UNREG +5 VDC supply.

Therefore, I can't see a compelling reason to change the resistors. The
Power On Reset is released later and the Low Power Reset is applied earlier
if all you do is replace the SAFT LX-1634 with a BR-2/3A. Would this be a
problem? Am I missing something?

Thanks for all the help in 2012 and Happy 2013.

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 Steve
Sent: Monday, December 31, 2012 7:34 PM
To: hp_agilent_equipment@... <mailto:hp_agilent_equipment%40yahoogroups.com>
Subject: Re: [hp_agilent_equipment] 3457a on the way

Joe and all,

I will pop the covers off mine again and have a look at the A1 board
revision number and resistor values. Regarding battery voltage, I noticed a
couple of web sites state that their lithium batteries are "3.6 v nominal,
3.4 volt operating" I assume that's at their rated current so HP may have
been stating operating voltage. I can't imagine that maintaining cal
constants would draw much current though.

Steve

On Dec 31, 2012, at 6:25 PM, "J. L. Trantham" <jltran@... <mailto:jltran%40att.net>
<mailto:jltran%40att.net> > wrote:

Steve, Jeff, and all,

My 2703Axxxxx 3457A also has the SAFT LX 1634, Lithium 3.0V, battery and

it

measures 3.032 VDC. Likewise, I can not see a date code on the battery,
even after removing the A1 Board and looking as far under the battery as
possible.

My A1 Board is 03457-665xx, REV A, 2703. According to the manual,

this is

the 'New Main Controller'. However, on my board, A11R644 is a 17.4 K
resistor and A11R645 is a 13 K resistor which represents the 'old'

resistors

and matches the schematic. The 'new' resistors would be 13 K and 12.7 K
respectively, according to the parts list and 'Changes'. The 'old'

battery

is listed as a 'Battery 2.9V .9A-HR Li/S-Diox W-Flex', according to the
Agilent website. Likewise, the Agilent website lists the 'new'

battery as
a

'Battery 3V 1.2A-HR Lithium Poly Carbon'. Only the manual parts list

lists

the 'new' battery as 3.4 V.

In addition, I don't think I have ever seen a 3.4 V Lithium battery.

So, the question is, when it comes time to replace the battery, what

should

be used?

Joe

-----Original Message-----
From: hp_agilent_equipment@...

<mailto:hp_agilent_equipment%40yahoogroups.com>
<mailto:hp_agilent_equipment%40yahoogroups.com>

[mailto:hp_agilent_equipment@...

<mailto:hp_agilent_equipment%40yahoogroups.com>
<mailto:hp_agilent_equipment%40yahoogroups.com> ] On Behalf Of Steve Krull

Sent: Monday, December 31, 2012 11:20 AM
To: hp_agilent_equipment@...

<mailto:hp_agilent_equipment%40yahoogroups.com>
<mailto:hp_agilent_equipment%40yahoogroups.com>

Subject: Re: [hp_agilent_equipment] 3457a on the way

Joe and all,

I just had a quick look inside my 3457A again. Mine has the 3.0 volt
lithium battery, SAFT LX-1634. Obsolete at Agilent, as is the newer
battery. Google was no help either. Mine measures 3.03 volts and

there's

no evidence of corrosion so that's good. I couldn't see a date code on
it; probably on the underneath side. I've replaced batteries by
paralleling the existing connections with an appropriate power supply
and then unsoldering the old battery with an isolated-tip iron and
soldering in the new battery. I've also carefully soldered a new

battery

in parallel with the old and then clipped out the old one. No problems
with lost data so far.

I'm not sure how the cal numbers increment. I'll have to experiment

with

that sometime. Right now I need to repair the 1349D display in my 8757A
so I can get on with a sweeper plug in project, so the volt-nuttery is
on hold for awhile.

Happy New Year to all!

Steve

On 12/30/2012 5:34 PM, J. L. Trantham wrote:

Steve,

Thanks for the data. Mine is also 2703A prefix with REV?:6,0 and
CALNUM?:98. Not a multiple of 34. Would be interesting to see what the
CALNUM increments by after an Agilent CAL.

I, too, need to look at the battery condition. I have not looked

at the

manual regarding replacing the battery. Has anyone done that without
losing
the CAL Constants?

Joe

-----Original Message-----
From: hp_agilent_equipment@...

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<mailto:hp_agilent_equipment%40yahoogroups.com>] On Behalf Of Steve
Sent: Sunday, December 30, 2012 4:14 PM
To: hp_agilent_equipment@...

<mailto:hp_agilent_equipment%40yahoogroups.com>
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Subject: Re: [hp_agilent_equipment] 3457a on the way

It would be interesting to see if a newer rev is out there. My 3457A
is s.n.
prefix 2703, with rev 6,0 and option 0, CALNUM=34. I wonder if

that's a

default number for anything less than a full cal at Agilent? The last
calibration was at least 6 years ago and performed by what was then

Boeing

Military Airplane Company's metrology lab. I need to open it up and

check

the battery condition.

Steve

On Dec 29, 2012, at 8:08 PM, "J. L. Trantham" <jltran@...

<mailto:jltran%40att.net>
<mailto:jltran%40att.net>

<mailto:jltran%40att.net>

<mailto:jltran%40att.net>
<mailto:jltran%40att.net> > wrote:

If the 'SELF TEST OK' message appears, there is no need to make any
'adjustments'. Just do the 'front panel CAL' if needed.

As I said, I would check it out, assume it is the best

instrument in

your

collection, send it to Agilent for CAL and see what you get.

I would appreciate knowing what 'REV?' and 'OPT?' says when you

get a

chance. 'CALNUM?' would be interesting as well.

In the 3458A, the firmware is in an EPROM (6 EPROM's for the older

units)

and can be removed, a socket placed, and easily upgraded by

purchasing the

latest pre-programmed EPROM (or EPROM's for the older units) from

Agilent.

The only problem is they have a $50 minimum for this $18 part

for the

later

units.

My wife thinks I am going to appear on an episode of 'Hoarders'.

Joe

-----Original Message-----
From: hp_agilent_equipment@...

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<mailto:hp_agilent_equipment%40yahoogroups.com>
<mailto:hp_agilent_equipment%40yahoogroups.com> ] On Behalf Of Jeff
Machesky

Sent: Saturday, December 29, 2012 8:01 PM
To: hp_agilent_equipment@...

<mailto:hp_agilent_equipment%40yahoogroups.com>
<mailto:hp_agilent_equipment%40yahoogroups.com>

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Subject: Re: [hp_agilent_equipment] 3457a on the way

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@...

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<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>
<mailto:hp_agilent_equipment%40yahoogroups.com>

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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>

<mailto:jeff%40codebest.com>

<mailto:jeff%40codebest.com>
<mailto:jeff%40codebest.com>

<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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