[volt-nuts] HP 3458A repair.

Wed Sep 18 23:28:51 EDT 2013

Just the one from the Agilent site.

If I get one of these, I'll hit Dave up for a good copy.

Thanks,
Tom

----- Original Message ----- 
From: "J. L. Trantham" <jltran at att.net>
To: "'Discussion of precise voltage measurement'" <volt-nuts at febo.com>
Sent: Wednesday, September 18, 2013 10:54 PM
Subject: Re: [volt-nuts] HP 3458A repair.

> Forgot to ask.
>
> Do you have the CLIP?
>
> Joe
>
>
> -----Original Message-----
> From: volt-nuts-bounces at febo.com [mailto:volt-nuts-bounces at febo.com] On
> Behalf Of John Phillips
> Sent: Wednesday, September 18, 2013 3:51 PM
> To: Discussion of precise voltage measurement
> Subject: Re: [volt-nuts] HP 3458A repair.
>
> I talked with Gary... it sounded more like a sales pitch like they replace
> relays before they failed. The date code on the cal ram is 6 years past
> replacement.  The only problem seems to be the amplifier/attenuator
> flatness. He said this could be caused by caps aging and changing value.
> They tried calibrating the AC but it did not come withing spec so they did
> not update the as left data... I think if they are going to send the as
> left data it should be real as left or blank. This meter looks like a good
> meter for what I will use it for so we will not use the AC above 2MHz as 
> if
> we ever did.
>
>
>
> On Wed, Sep 18, 2013 at 9:17 AM, J. L. Trantham <jltran at att.net> wrote:
>
>> I agree with your assessment of an 'old' meter being more desirable.
>>
>> I would recommend a conversation with Gary Bierman if you have not 
>> already
>> done that.
>>
>> Joe
>>
>> -----Original Message-----
>> From: volt-nuts-bounces at febo.com [mailto:volt-nuts-bounces at febo.com] On
>> Behalf Of John Phillips
>> Sent: Wednesday, September 18, 2013 10:45 AM
>> To: Discussion of precise voltage measurement
>> Subject: Re: [volt-nuts] HP 3458A repair.
>>
>> The meter will be here in a few days. I did buy the ram. As far as the
>> meter
>> age goes, unless it is a very old hardware revision, I would rather have
> an
>> old meter because it is more stable. That is until it brakes.
>>
>> I do have before and after readings and the 4 readings are the only ones
>> that failed. The after readings are better than the before readings.
>> Because the 8 and 10 MHz failed we did not get a certificate but we do
> have
>> a good limited calibration up to 2 MHz. Just no official cal.
>>
>> The cal we wanted was $1600. We will still have to pay that after the
>> repair.
>> From what I can tell they did not run SCAL or the before/after readings
>> would not have matched. Like they really did not run after readings or
>> there
>> would have been some mismatch.
>>
>>
>>
>>
>>
>> On Tue, Sep 17, 2013 at 6:50 PM, J. L. Trantham <jltran at att.net> wrote:
>>
>> > John,
>> >
>> > Can you give us more information?  Serial number, Rev. number, CALNUM?
>> > How much to invest will be determined by age and other condition.
>> >
>> > It doesn't sound like a simple CALRAM issue but changing the CALRAM is
>> > relatively easy.  I removed all three DALLAS chips in mine and
>> > installed sockets.  The CALRAM can be read with a chip programmer and
>> > the data written to a new DALLAS chip.
>> >
>> > I would also call Gary Bierman at the Loveland Cal Lab and have a long
>> > talk with him.  He has a lot of insight into these meters and
>> > generally prefers to do a component level repair rather than an
>> > assembly level repair.  The charge sounds like their standard repair
>> > charge, no matter what the problem is, and includes a 'fresh
>> > calibration' along with a warranty, a year I think, but Gary will be
> able
>> to answer that question.
>> >
>> > Also, once you get the meter calibrated by Agilent (and thus prove it
>> > is functioning normally) it will be eligible for their 'repair
> agreement'
>> > which
>> > is $178.68 per year.  I would consider buying a 5 year agreement after
>> > the repair.
>> >
>> > Good luck.
>> >
>> > Joe
>> >
>> > -----Original Message-----
>> > From: volt-nuts-bounces at febo.com [mailto:volt-nuts-bounces at febo.com]
>> > On Behalf Of John Phillips
>> > Sent: Tuesday, September 17, 2013 3:36 PM
>> > To: Discussion of precise voltage measurement
>> > Subject: [volt-nuts] HP 3458A repair.
>> >
>> > Hi,
>> > I have a 3458A that we sent to Agilent for calibration which it failed.
>> > Before we sent it we calibrated it and it looked good to us. The
>> > infor. we revived led us to believe that the cal memory may have caused
>> the failure.
>> >  We ask that it be sent buck to us and paid half the cal charges
>> > (about
>> > $800) insted of the $2660.64 they wanted to repair it. We were just
>> > going to repalce the ram in try again.
>> > When we got the meter back it came with befor and afer data Like
>> > before 10 volts read 9.9999957 and after it read 10.00009 so they did
>> > something or the meter drifted that much.
>> > The problem is  0.1 volt and 1.0 volts failed at 8 and 10 MHz but
>> > passed at
>> > 4 MHz.
>> > 4MHZ 0.1 volt reads 0.097251 Lower Limit is 0.095930 PASSED 8MHZ 0.1
>> > volt reads 0.085712 Lower Limit is 0.0959
>> > 2
>> > 0
>> > FAILED
>> > 10MHZ 0.1 volt reads 0.75569 Lower Limit is 0.084900 FAILED
>> >
>> > 4MHZ 1 volt reads 0.97272 Lower Limit is 0.95930 PASSED 8MHZ 1 volt
>> > reads
>> > 0.86389 Lower Limit is 0.95920 FAILED 10MHZ 1 volt reads 0.73514 Lower
>> > Limit is 0.84900 FAILED
>> >
>> > The AC after readings are the same. I do not see how AC after could be
>> > that identical even if they did not try to calibrate it. Did they just
>> > copy the before data and call it after data?
>> >
>> > My best guess is that if the 4 MHz is in and the higher frequencies
>> > are not the meter requires some kind of mechanical adjustment to get 
>> > the
>> frequency
>> > response   withing spec or the AC board needs to be repaid.
>> >
>> > Are they charging a standard repair charge to do a calibration? I do
>> > not see changing the memory to fix this.
>> >
>> > Where would you go from here if this was your meter?
>> >
>> >
>> > --
>> > John Phillips
>> > _______________________________________________
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>>
>>
>>
>> --
>> John Phillips
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>
>
>
> -- 
> John Phillips
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