[volt-nuts] What's the probability of a random used 3458A passing a Keysight calibration?

[Dr. David Kirkby]

On 16 January 2018 at 17:33, Dr. Frank <frank.stellmach at freenet.de> wrote:

> I meant to say, that the ADC ASIC determines crucially the stability.. and
> this special serial number US28032500 is eventually affected by the AN-18
> service note. So that may be the reason, why they claim 2100$ for repair,
> i.e. replacement of A5, the ADC PCB.. and that had nothing to do with that
> ACV outlier. The "as left" data is not displayed, probably the instrument
> was completely adjusted afterwards. The cal report is also not online, pity.
>
> So I wouldn't touch that instrument at all, as the ADC drift problem
> (CAL?72) is not checked.
>
> Frank
>

I don't think it was adjusted, because if you look in the front, the
Keysight cal sticker says "Conditional cal".

My understanding is that a Keysight calibration will include any
adjustments needed, without extra payment.

See for example

https://literature.cdn.keysight.com/litweb/pdf/5990-6245EN.pdf

"Instrument adjustments included at no extra charge, when out-of tolerance
condition is found" That applies to any of the Keysight calibrations - even
the most basic non-accredited one.

I read AN-18, and see

Serial Numbers: US28031400 / US28032927

I assume that means it applicable to instruments with serial numbers in the
range US28031400 to US28032927, although it could have been a bit more
clearly written.

The application note mentions the A3 board, 03458-69503, not the A5 board.
Was A5 a typo, or is there something else?

If one see a used 3458A with a serial number in that range, is there a way
of determining if the board has been replaced or not?  I assume the part
number of board would tell you, but that may not be easy to see. Is there
any sequence of key presses that will determine if the board has been
replaced?