[volt-nuts] volt-nuts Digest, Vol 12, Issue 11

[Roy Phillips]

Dick
I have read the exchanges on the subject of the HP3458A with considerable 
interest.  I purchased a working 3458A about a year ago from a source which 
in turn had obtained it from a large Companies Lab. when it closed down.  It 
was in pretty good condition overall, but it has the ROM board with the 
Dallas ROMs'  fitted, and I await the day in trepidation when they "run 
out", but I would prefer to replace the board as you have, with the later 
type.  As for calibration, mine was last cal'd by Agilent (here in the UK) 
on 27/02/2007 with a next cal due date of 27/02 /2009. To date the 
instrument has performed faultlessly. I anticipate that to replace the ROM 
board with one obtained from Agilent UK would be very expensive, judging 
from prices for other HP equipment replacement/repair prices. As you may 
know, we in the UK usually pay the same amount in UK pounds that you in the 
US pay in dollars. Has anyone in the UK purchased this item ?
Best regards.
Roy


--------------------------------------------------
From: "Dick Moore" <richiem at hughes.net>
Sent: Wednesday, August 25, 2010 8:26 PM
To: <volt-nuts at febo.com>
Subject: Re: [volt-nuts] volt-nuts Digest, Vol 12, Issue 11

> Hi, Marv -- RE my 3458 -- It was very clean externally, leading me to 
> think it had been used in a test or lab environment, but it needed a 
> display board and a ROM board, both of which I installed. Then it went to 
> Loveland for calibration. That was last September. Because the ROM board 
> was replaced, there was no "before" data to compare the cal to. It goes 
> back to Loveland this September, and now there will be "before" and 
> "after" data which will provide an estimate of drift in parameters. It is 
> not an -02 high-stability option unit.
>
> The ROM board change essentially made this a good-as-new unit, at least 
> according to Loveland -- it passed all pre-cal tests with flying colors 
> and cal'ed without problems.
>
> I believe that Loveland uses a Fluke 572x calibration system, which for DC 
> is at least as good as the 732B. As to AC -- well I think it probably is 
> as good as there is right now for cal use outside of labs. The specs for 
> the 3458 reflect the uncertainty of the calibration standards, and the AC 
> specs definitely show that. I bought that 3458 for $1600 on fleabay --  
> didn't want to pay too much more because of the ROM battery problems on 
> older units with the Dallas ROMs that had built-in battery back up. The 
> new ROM board has ROMs that have a snap-on battery which is apparently 
> easy to replace, though I wonder how long they will be available via 
> Agilent....
>
> In any case, the display board was $400+, the ROM board was $500+ and the 
> cal was about $500, so my total investment to this point is around 
> $3100 -- a lot, but worth it. I just trust the 3458 without wondering if 
> it is right. It is the only high-res measurer in the shop now, so it is 
> right by definition. As Steve Rooke likes to say, "A man with one clock 
> knows what time it is. A man with two clocks isn't ever sure."
>
> Best,
> Dick Moore
>
>
> On Aug 25, 2010, at 5:00 AM, volt-nuts-request at febo.com wrote:
>
>> Message: 1
>> Date: Tue, 24 Aug 2010 19:52:37 -0400
>> From: "Marvin E. Gozum" <marvin.gozum at jefferson.edu>
>> Subject: Re: [volt-nuts] Back to voltage
>> To: Discussion of precise voltage measurement <volt-nuts at febo.com>,
>> volt-nuts at febo.com
>> Message-ID: <6.2.5.6.2.20100824183805.0504e360 at jefferson.edu>
>> Content-Type: text/plain; charset="us-ascii"; format=flowed
>>
>> Hello Dick,
>>
>> Thanks for your input.  Your posts on time-nuts have been invaluable
>> as was the thread here and all its contributors:
>>
>> http://www.mail-archive.com/time-nuts@febo.com/msg16497.html
>>
>> The last I read on time and volt nuts, your HP 3458a had it share of
>> trouble, but you describe here its working true now, did it take much
>> to get back into factory shape?
>>
>
>
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