[volt-nuts] 3458A - To Modify or Not To Modify?

Tue Nov 8 02:00:20 UTC 2011

Joe,

Does sound like toast... Bummer.

Steve

On Nov 7, 2011, at 7:37 PM, "J. L. Trantham" <jltran at att.net> wrote:

> Steve,
> 
> Got em.  U132 image is TOTALLY different from mine and much more of what I
> expected.
> 
> I re-read U132 and it is somewhat different every time I read it.  Sounds
> like it is 'toast'.
> 
> Joe
> 
> -----Original Message-----
> From: volt-nuts-bounces at febo.com [mailto:volt-nuts-bounces at febo.com] On
> Behalf Of Steve
> Sent: Monday, November 07, 2011 7:20 PM
> To: Discussion of precise voltage measurement
> Subject: Re: [volt-nuts] 3458A - To Modify or Not To Modify?
> 
> Joe,
> 
> On the way!
> 
> Steve
> 
> 
> 
> On Nov 7, 2011, at 7:14 PM, "J. L. Trantham" <jltran at att.net> wrote:
> 
>> Steve,
>> 
>> I would love to see them.
>> 
>> Joe
>> 
>> -----Original Message-----
>> From: volt-nuts-bounces at febo.com [mailto:volt-nuts-bounces at febo.com] On
>> Behalf Of Steve
>> Sent: Monday, November 07, 2011 6:07 PM
>> To: Discussion of precise voltage measurement
>> Subject: Re: [volt-nuts] 3458A - To Modify or Not To Modify?
>> 
>> Joe,
>> 
>> I have the images from the chips in my 3458A. They had '94 dates so a few
>> months ago I unsoldered them, read them, installed machined-pin sockets
> and
>> burned new chips, and the meter came up with no problems. I hope to send
> it
>> to Loveland soon. I'm on the road for the week but have asked a fellow ham
>> to send me a copy of the files as we did the reading and burning at his
>> place.
>> 
>> Steve
>> 
>> Sent from my iPad
>> 
>> On Nov 7, 2011, at 5:23 PM, "J. L. Trantham" <jltran at att.net> wrote:
>> 
>>> Bill,
>>> 
>>> I don't know if I have damaged my 'cal' DS1220Y or not.  The two
> DS1230Y's
>>> had files that looked like what I was expecting when I read them.  On the
>>> DS1220Y, the original read on my BP-1600 gave an over current warning and
>>> shut down.  The chip was a bit warm from the unsoldering and, perhaps,
>> that
>>> was it.  I then moved it from my BP-1600 to an Advin MVP and it read
>>> promptly.  I then re-read it on the BP-1600 and it read promptly.  So,
>> don't
>>> know.  Would be nice to find an image to compare with just to get an idea
>>> about what it should look like.
>>> 
>>> That chip had a date code of 9713 and the two DS1230Y's were 9703.
>>> 
>>> In any event, new sockets and chips are on the way.  If I have lost my
>>> calibration constants, I would anticipate that the meter is still
>> 'calable'
>>> which is what I am hoping for.  Then, once it gets back from Agilent, I
>> will
>>> be able to harvest the data from the new chips, archive it, and be in
>>> business the next time the chips fail.  Then, again, my current chip may
>>> still be OK.
>>> 
>>> Joe
>>> 
>>> -----Original Message-----
>>> From: volt-nuts-bounces at febo.com [mailto:volt-nuts-bounces at febo.com] On
>>> Behalf Of Bill Gold
>>> Sent: Monday, November 07, 2011 11:31 AM
>>> To: volt-nuts at febo.com
>>> Subject: Re: [volt-nuts] 3458A - To Modify or Not To Modify?
>>> 
>>> 
>>> Joe:
>>> 
>>>  When I removed my original NVRAM, put in the sockets and then installed
>>> the original NVRAM I got a few error messages when I turned the meter
> back
>>> on.  I don't remember exactly what the complaint was but it involved a
> few
>>> calibration constants missing and the calibration password missing.  My
>>> initial guess was that the batteries were gone and desoldering the NVRAM
>>> just finished the process.  The date codes on the NVRAM was 1989 so I was
>>> just running on borrowed time anyhow.
>>> 
>>>  I don't have a ROM programmer anyhow so I just installed the new NVRAM
>>> and did a full calibration to my local standards.  I really don't care
>> about
>>> traceability to NIST anyhow.  What I have here is close enough for what I
>>> do.
>>> 
>>>  I have tried to find out what material is used for the pins of the
>> NVRAM
>>> is but no such luck from the Maxim/Dallas package datasheets.  My guess
>>> would be the usual tin plate.  Yes, gold against tin isn't the best idea,
>>> but it is better than tin against tin.  You are simply not going to find
>>> these NVRAM with gold plated pins so you have no choice.  I forget
> whether
>>> the gold migrates into the tin or the tin migrates into the gold.  When
> we
>>> specified the plating of the "fingers" of our PC Boards, we used nickel
>> over
>>> the copper and then 60u of gold over the nickel.  This gave the best
>> results
>>> for constant insertion and removal of the PC Boards from the mother board
>>> sockets, which were gold plated.  We produced expensive ATE for Discrete
>>> Semiconductors, in the range of $100k to $200k each, so we wanted
>>> absolutely, positively good contact all the time and no failures due to
>>> repeated removal and insertion.
>>> 
>>>  IMHO you are on the right track.  Let's see what happens when you
>>> finally get the Loveland calibration.
>>> 
>>> Bill
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