Pair of 3458A DMMs being sold by Keysight. Cal question - Page 1
Forum section: electronics / testgear

author: Jwalling
author_rank: Unknown
timestamp: July 09, 2018, 10:33:38 am
content: https://www.ebay.com/itm/183316257302?https://www.ebay.com/itm/192593612639?I'm curious about what the calibration documents are saying about these in the "as completed conditions".Anyone?

author: Shock
author_rank: Super Contributor
timestamp: July 09, 2018, 10:42:28 am
content: Double talk for, it seems to be working but they can't calibrate it fully and certify it.

author: iainwhite
author_rank: Unknown
timestamp: July 09, 2018, 11:08:22 am
content: There is an explanation of measurement uncertainty on the NIST websitehttps://physics.nist.gov/cuu/Uncertainty/coverage.htmlAs far as I can guess, the 3458A has been measured to be accurate, but it is failing the portion of the tests dealing with measurement uncertainty(which I assume is mostly statistical analysis, rather than actual measured values).

author: TiN
author_rank: Super Contributor
timestamp: July 09, 2018, 11:08:46 am
content: Boxes were out of spec, then were adjusted, but still provided marginal data. Might be drifty or otherwise problematic, which caused measured parameter to be out of guardband expected levels.

author: HighVoltage
author_rank: Super Contributor
timestamp: July 09, 2018, 06:44:21 pm
content: These are not bargain offers by Keysight for the prices shown.It might take a lot of money to make them perfect.

author: Kleinstein
author_rank: Super Contributor
timestamp: July 09, 2018, 09:28:07 pm
content: For some reason they do not show which function is not working properly (higher than normal error). Due to the ACAL way used the ranges are linked together - so it would really help to know which ranges are not working. So it's a kind of B quality instrument that might be OK for some cases, but not a fully functional meter. It looks like the defect is not that easy to repair (e.g. bad reference module) and so they sell it for a reduced price instead.Before buying I would try to get detailed info on which specs are not fully met - it may or may not effect you needs, but still expensive for a gamble. Some errors are more serious than others.

author: TheSteve
author_rank: Unknown
timestamp: July 09, 2018, 09:33:16 pm
content: I'm surprised they would sell anything that is not 100% on the webstore.It is odd for a manufacturer to do that.

author: orin
author_rank: Frequent Contributor
timestamp: July 09, 2018, 09:53:19 pm
content: I'd ask if they qualify for their $204 a year repair agreement... If not, IMO there's no way they are worth the asking price.

author: JonM
author_rank: Unknown
timestamp: July 10, 2018, 02:22:50 am
content: Hmmm, a used 8.5 digit DMM with questionable calibration by the manufacturer for more than 2x what a new 7.5 digit 34470A costs?Maybe I am missing something about why the 3458A is so desirable beyond the 8.5 digits.

author: TiN
author_rank: Super Contributor
timestamp: July 10, 2018, 04:25:23 am
content: JonM, 3458A will run circles around 34470A for stability, noise performance and accuracy and best on market linearity.34470A is bench meter (a good one), while 3458A is reference meter, so they are build and tested to very different purposes.While the later can be used as bench meter, it's not what it is best for. That is a reason why 3458A designed late 80's is still manufactured and sold new today.

author: AG7CK
author_rank: Regular Contributor
timestamp: July 10, 2018, 11:53:00 am
content: Quote from: TheSteve on July 09, 2018, 09:33:16 pmAgree.However, having seen their video lottery circus with the new low end scopes and the laughable black-red "free" test equipment software, nothing amazes me anymore. Not even this:They list the discontinued 6632B power supply which everyone knows you can buy on eBay for USD 100 (give or take a few) with the list price before it became " This product is no longer available ":Copy and paste from eBay link below:---------------------------------------------------------------------------------------------Keysight Used 6632B DC power supply, single-output. 0-20 V, 0-5 A,100W (Agilent)List price:$3,187.00You save:$2,549.60 (80% off)Now:US $637.40----------------------------------------------------------------------------------------------https://www.ebay.com/itm/Keysight-Used-6632B-DC-power-supply-single-output-0-20-V-0-5-A-100W-Agilent/182614181507?hash=item2a84a74683:g:7DAAAOSwCmZZOvNuSave$2,549.60 !?I would be embarrassed. Are they out of their mind?

author: HighVoltage
author_rank: Super Contributor
timestamp: July 11, 2018, 08:25:55 am
content: I am surprised the 6632B was still produced under the Keysight label.I think I paid like Euro 130 for a "like new" 6632B with Agilent label.Also a surprise on the two 3458A on ebay is the list price.The older unit has a list price of $9,993 and the newer has $10,712Wasn't the list price much lower, when the HP unit was built.Some other ebay units are in much better conditions and much lower price.But who knows, may be they would accept a much much lower offer.