[volt-nuts] HP 3458A repair.

Tom Miller tmiller11147 at verizon.net
Thu Sep 19 00:53:55 EDT 2013


OOPs, disregard. I tangled it with another message.


Tom

----- Original Message ----- 
From: "Tom Miller" <tmiller11147 at verizon.net>
To: "Discussion of precise voltage measurement" <volt-nuts at febo.com>
Sent: Wednesday, September 18, 2013 11:28 PM
Subject: Re: [volt-nuts] HP 3458A repair.


> 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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>
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