FS UK: Agilent 3458A 8.5 digit DMM - Page 1
Forum section: electronics / general

author: voltsandjolts
author_rank: Unknown
timestamp: October 21, 2023, 01:23:49 pm
content: This is not my auction, I have no connection with the seller, just pointing this out for the volt nuts.Starting bid £2350https://www.ebay.co.uk/itm/225827704316QuoteI think somebody on this forum said (half-joking) the only 3458A's on ebay are the drifty ones no one wants, so buyer beware.

author: coromonadalix
author_rank: Super Contributor
timestamp: October 22, 2023, 01:10:45 am
content: yes the a3 board problem if i recall ??https://eevblog.com/forum/metrology/hp-3458a-ad-board-spare-part-availibilty-and-cost/see post #225

author: alm
author_rank: Super Contributor
timestamp: October 22, 2023, 07:57:17 am
content: 5 units are an anecdote, not data. There is certainly a substantial risk that it's drifty, and the problem is that you probably won't find out until the return period is over. But I bought two early units from 1989-1991 and both are stable (n=2) (knock on wood).

author: voltsandjolts
author_rank: Unknown
timestamp: October 22, 2023, 04:31:30 pm
content: Is £2500 a fair price for a drifty example?Not that I want to get into this volt nuttery, but it does intrigue me.It feels like purchasing this would almost be like adopting a child, although easier to sell onIt needs care and investment for the long term. Constantly powered in a cosy environment.

author: coromonadalix
author_rank: Super Contributor
timestamp: October 23, 2023, 12:24:38 am
content: absolutely not, like having an formula 1 car with a 4 cylinder at 80 hpif the a3 board is drifty it will cost lots of $ to get one, or try to send you meter to keysight ... and lots $$$ to get it repaired and calibratedand sadly ebay sellers may or may not know if their meter is problematic without the proper tests

author: voltsandjolts
author_rank: Unknown
timestamp: October 23, 2023, 03:13:23 pm
content: It's probably worth £2500 broken up for parts.And if it's not drifty, it's a bargain price 3458A.But I've got a cluttered bench already.No. Nope. No way. Hmm, well....

author: chilternview
author_rank: Frequent Contributor
timestamp: October 23, 2023, 04:00:25 pm
content: I'd be tempted but I already have twoDon't forget that a Keysight cal is going to set the buyer back nearly £1k - and why buy one if you're not going to be sure it's in cal?

author: alm
author_rank: Super Contributor
timestamp: October 23, 2023, 04:11:50 pm
content: Quote from: chilternview on October 23, 2023, 04:00:25 pmBecause of the excellent linearity? For metrology-grade measurements I use mine purely as ratio devices. I have better voltage and resistance standards: the 3458A's built-in DCV and resistance reference are pretty good but not amazing. So for me the 3458A is generally just measuring the ratio between the DUT and an external reference. And thanks to the magic of the extremely linear ADC and autocal, it can accurately measure those ratios without any external calibration. The exception is high frequency ACV, but those specs aren't so hot anyway. The only thing that would make it even better is if the front/rear inputs could be switched under remote control.If you want to rely on its absolute values then you might want to send it out for calibration, but I don't consider that essential for my use.

author: chilternview
author_rank: Frequent Contributor
timestamp: October 23, 2023, 04:19:46 pm
content: Quote from: alm on October 23, 2023, 04:11:50 pmAgreed, if the user has better standards that they can trust that's certainly a valid use model.

author: coromonadalix
author_rank: Super Contributor
timestamp: October 23, 2023, 05:32:40 pm
content: i think the 3458 just needed 2 thingsa very stable reference voltage and an precise resistor value to calibrate it

author: alm
author_rank: Super Contributor
timestamp: October 23, 2023, 10:16:49 pm
content: To adjust everything but high frequency AC, you're right, you just need a very stable 10Vish DC voltage source and 10 kOhm ish resistor that you know the value of very accurately, plus a good short. The manual tells you how to make it out of a piece of copper wire. I'd argue just running this is good enough for most hobby use.But for a proper calibration you should also verify all ranges and functions afterwards. How else can you verify uncertainties or get a report with data? That's what Keysight does if you send it to them.

author: chilternview
author_rank: Frequent Contributor
timestamp: October 24, 2023, 02:26:48 am
content: Of course you need to know if your voltage and resistance reference is 'accurate'.... is it calibrated, what is its uncertainty, what is it traceable to, how much may it have drifted due to temperature and/or ageing. And do you need an accredited calibration - all depends on what you want to use the 3458A for.

author: deepfryed
author_rank: Unknown
timestamp: October 25, 2023, 12:21:59 am
content: Quote from: voltsandjolts on October 21, 2023, 01:23:49 pmOut of curiosity, emailed the seller last night to ask if there's any paperwork on history / calibration & adjustments. No responseIf someone on the forum buys it, I'd be interested to know how it turns out

author: Oldtestgear
author_rank: Regular Contributor
timestamp: October 26, 2023, 12:51:04 pm
content: I have sold a couple of 3458A DMMs over the years. I always checked for drift before selling AND showed the data. Specifically excluding drift in a listing screams "I know it drifts".Just my opinion but I would not pay anything like the starting price on what is a huge gamble.Phil

author: factory
author_rank: Super Contributor
timestamp: October 26, 2023, 05:13:10 pm
content: Or zero history and ERR on display...https://www.ppauctions.com/lot/185406/lot-1528Not interested myself.David

author: alm
author_rank: Super Contributor
timestamp: October 26, 2023, 08:42:52 pm
content: Quote from: factory on October 26, 2023, 05:13:10 pmIt's always a risk, some more than others. For GBP 480 I would absolutely buy it, but I'm sure it won't stay like that. The ERR annunciator could be something innocent like the digital NVRAMs for reading stories having an empty battery, or something as big as needing a new A3 board. You have these risks with most used equipment in unknown condition, it's just that the stakes are higher here because of the repair costs. However, expect to pay a lot more for a unit with a documented drift history because obviously these are more desirable.

author: veedub565
author_rank: Frequent Contributor
timestamp: October 26, 2023, 09:13:42 pm
content: Quote from: factory on October 26, 2023, 05:13:10 pmI saw that and put a bid on around £400 (+VAT +fees). Not a bad price still, but I doubt it'll sell that cheap. And I already have a calibrated Datron 1281 so I don't desperately need the 3458a, although it would be nice to have.

author: bastl_r
author_rank: Regular Contributor
timestamp: October 27, 2023, 06:57:13 am
content: I cannot make an offer because there is "no shipping to germany" marked.

author: Oldtestgear
author_rank: Regular Contributor
timestamp: October 27, 2023, 09:18:31 am
content: I have just looked at the 3458A being auctioned by PP Auctions. It was sent to Keysight in January this year -- see electrical safety check label -- but no sign of a calibration label.Bit strange unless it was returned as "unrepaired" or someone has peeled the calibration sticker off to try & get a great deal? Either way it is now too expensive for me to take a punt on...........Phil

author: chilternview
author_rank: Frequent Contributor
timestamp: October 27, 2023, 10:34:10 am
content: Quote from: Oldtestgear on October 27, 2023, 09:18:31 amYep. No cal label almost certainly means it failed, else why put it up for auction? At £1250 already its looking expensive as repair and cal is going to be in the £3k range.

author: factory
author_rank: Super Contributor
timestamp: October 27, 2023, 12:32:11 pm
content: I'm suspicious that the high bidder is an alias of "reserve not met", think this will be appearing in quite a few future auctions.Might give anyone seriously interested a chance to ask Keysight about the S/N and research if it's failed cal.The company work outsourced calibration to still puts cal-due labels on failed items, even though it also states failed.David

author: mendip_discovery
author_rank: Super Contributor
timestamp: October 27, 2023, 01:18:09 pm
content: Quote from: factory on October 27, 2023, 12:32:11 pmEither a punt for nothing or a shill to get it moving.QuoteThey don't like customers let alone someone asking for a cert/details for free.QuoteIf I reject something it gets a cal date but where the due date is I put rejected. But I know from a 17025 (UKAS) that they feel it should be for the customer to decide so I have to use a "Limited Calibration see Certificate" label. But they also get funny about us putting due dates on things as it is for the customer to decide, the 12-month thing is a really lazy option and was mostly promoted by companies that wanted you to send the stuff back to them each year. If a customer doesn't state a frequency we just leave it blank.

author: macaba
author_rank: Regular Contributor
timestamp: October 27, 2023, 01:45:42 pm
content: Quote from: factory on October 26, 2023, 05:13:10 pmApprox. £3222.45 for a unit with a multislope rundown convergence error. Madness.

author: chilternview
author_rank: Frequent Contributor
timestamp: October 27, 2023, 02:01:03 pm
content: Quote from: macaba on October 27, 2023, 01:45:42 pmJust curious, but how do you know that? Did you go view it before auction?

author: factory
author_rank: Super Contributor
timestamp: October 27, 2023, 02:59:04 pm
content: Or maybe asked the auction house to run the self test, or asked them for the error code, not an unreasonable request given what these make. Or asked Keyshite for a cal/repair quote against that S/N.I'm 99.99% certain the house won it.David

author: factory
author_rank: Super Contributor
timestamp: October 27, 2023, 03:25:25 pm
content: Quote from: mendip_discovery on October 27, 2023, 01:18:09 pmIn the past we had several people employed full time doing internal cal (with very little done externally) this got slowly reduced, by sending stuff to various external different external cal companies, with less done in house.More recently those in charge want rid of the internal cal lab, they choose one company to send everything to, with a fixed yearly contract price (repairs not included), not sure if they choose based on, what was easiest for them, or the cheapest option.They seem to be giving the same cal intervals, six or twelve months as in house did. When you say "customer" this will mean whoever is in charge will decideifthey even notice.It'll probably fall apart when a auditor finds one of the barely noticeable "fail"s on a cal label, some of us know what to look for & put out of use, but not all will.David

author: mendip_discovery
author_rank: Super Contributor
timestamp: October 27, 2023, 05:43:21 pm
content: It sold, for £3275David, lots of companies have gone for this method, as they want to get rid of the hassle of dealing with calibration. The thing for me is very few of them ever look at a certificate and ask is this fit for purpose and if this item meets the requirements for being used? This I feel in a sensible sized company could almost be a full time job.

author: pope
author_rank: Frequent Contributor
timestamp: October 27, 2023, 08:31:07 pm
content: Quote from: mendip_discovery on October 27, 2023, 05:43:21 pmTo me it shows that it sold for £2,325

author: chilternview
author_rank: Frequent Contributor
timestamp: October 27, 2023, 09:08:49 pm
content: Quote from: pope on October 27, 2023, 08:31:07 pm

author: factory
author_rank: Super Contributor
timestamp: October 27, 2023, 09:47:12 pm
content: £2325 + VAT + auction fees was the one from PP auction, not ePay.David

author: bastl_r
author_rank: Regular Contributor
timestamp: October 28, 2023, 01:00:24 am
content: Apart from the fact that the device has become too expensive for me, no matter how good it still is.How would it compare to a 7.5 digit meter. My feeling is that with the possible errors discussed, it should still be at least half a decade more accurate than a 7.5 digit multimeter.Or?

author: voltsandjolts
author_rank: Unknown
timestamp: October 28, 2023, 08:27:16 am
content: An out of spec 3458A 8.5 digit metercouldbe as accurate as a 7.5 digit DMM, but you would still need the ~£2K Keysight cal to show show how out of spec it was

author: coromonadalix
author_rank: Super Contributor
timestamp: October 28, 2023, 10:31:37 am
content: We dont hear a lot of the ADCMT Transmill or the Fluke 8.5 digits or any 8.5 digits meters ...If they have some quircks like the 3458EDITAdvantest R6581 ??

author: Oldtestgear
author_rank: Regular Contributor
timestamp: October 30, 2023, 11:27:26 am
content: Or the Solartron 7081 *.5 digit DMM. Although there are a few threads about these on the forum. Nice clear display but definitely a bit quirky.Phil

author: MadTux
author_rank: Frequent Contributor
timestamp: October 30, 2023, 02:40:02 pm
content: Quote from: coromonadalix on October 28, 2023, 10:31:37 amIf ADC is build without hybrids like U180, at least it's most likely more DIY fixable.With HP3458A, you totally depend on Keysight for support, something I'd rather avoid.

author: alm
author_rank: Super Contributor
timestamp: October 30, 2023, 04:12:46 pm
content: Quote from: MadTux on October 30, 2023, 02:40:02 pmAre schematics available for the Fluke or Transmille meters like they are for the 3458A?

author: coromonadalix
author_rank: Super Contributor
timestamp: October 30, 2023, 04:32:32 pm
content: dont think so, never heard of leaked ones, you have some but no schematics for sure lollFluke 8xxx never sawAdvantest r6581 never sawhttps://xdevs.com/fix/r6581t/Transmille 8081 never sawthe 3458A is known lollK2002 cant remember ... don't think so, k2000 was partiallySolartron 7081 i think it is known, some float on Archive.org

author: Kleinstein
author_rank: Super Contributor
timestamp: October 30, 2023, 04:50:20 pm
content: The Solartron 7081 eventually gets 8 digits, but with less than 1/10 the speed and a little residual drift and somewhat troubled auto zero to correct for this.AFAIK there are no schematics avialable for the new fluke and the transmile meters. For the slightly older (AFAIK not current) transmile meter there is a thread here in the forum that has some testing and reverse engeniering one the ADC. From that it looks a bit like the Solartron with added oddities. Without a schematics and service hints this could be hard to fix / test and a programmed µC or CPLD can already be a show stopper if bad.There are full service docs on the Datron1281, the predecessor to the high end Fluke meters.For the Solartron 8081 there is a plan around.For the K2002 there is partial rev. engeniering (ADC, ohms part and crude voltage part) and a useful service manual to at least explain the self test errors.For the R6581 there are quite good rev. eng. plans and even firmware analysis around here in the forum.Still not all 8 digit meters are at the same level.

author: alligatorblues
author_rank: Regular Contributor
timestamp: December 30, 2023, 03:32:58 pm
content: Quote from: voltsandjolts on October 21, 2023, 01:23:49 pmSemiconductor manufacturers use many 3458As. When they get drifty, not even out of spec, they turn them over to liquidators, and some find their way to eBay. The A3 boards come up on eBay a few times a year. You just need to save the search, and when one comes up, you'll get an email.You just never know. Last time I needed one, a soldier on a military base had 25 of them. He probably found a box of them and knew what they are. If you go on military calibration forums, those guys can get anything you want. But you have to get to know who's who.Defense contractors also have cal labs everywhere. So, their techs are there too. Lockheed Martin does calibration work for commercial labs, but it's very hush hush how to find the labs that are open to the outside world. I found one in FL USA. But it only does pick up and drop off.

author: Oldtestgear
author_rank: Regular Contributor
timestamp: December 31, 2023, 12:02:41 pm
content: QuoteI just paid for Keysight UK to calibrate my 3458A, at the bargain price of "only" £716.40. Note no adjustments performed.Getting a 34470A calibrated cost £247.20 which included pre & post adjustment results. The Instrument was within specification before adjustment but this was performed as part of the job.All prices included VAT

author: voltsandjolts
author_rank: Unknown
timestamp: December 31, 2023, 12:24:10 pm
content: Oh, bargain!You state prices including VAT but theywouldn't deal with you as a private individual, have I got that right?Quote from: Oldtestgear on September 28, 2021, 02:36:10 pmExcluding my shipping costs to/from your office, how much would you charge to get my 34470A cal'd at Keysight, with adjustments?

author: coromonadalix
author_rank: Super Contributor
timestamp: December 31, 2023, 02:16:36 pm
content: there's a difference between certification AND calibration

author: voltsandjolts
author_rank: Unknown
timestamp: December 31, 2023, 02:55:27 pm
content: I have a plethora of certificates of calibration.I don't have any certificates of certification.

author: coromonadalix
author_rank: Super Contributor
timestamp: December 31, 2023, 03:04:58 pm
content: in my country,Certify the instrument work in the acceptable range or outside of the acceptable range, no calbrationCalibration, it was certified before, got the results, and calibrate it, adjustment done internally or software made etc ...a calibration can be done, AND it can get a failed status on some ranges, failed on 1 range or failed on all .... because it still can not get under the acceptable rangesnormally the certification will tell all, and the user have to choose if he / she goes thru the Calibrationmostly the Cal labs : you can not calibrate until a certification was made prior, everything is logged ... that's how they work in my town

author: alm
author_rank: Super Contributor
timestamp: December 31, 2023, 04:20:19 pm
content: Quote from: coromonadalix on December 31, 2023, 03:04:58 pmWhat country is that, that is not amember of the BIPM, and does not adhere to theInternational Vocabulary of Metrology(see section 5.18 / page 39)?

author: coromonadalix
author_rank: Super Contributor
timestamp: December 31, 2023, 04:58:53 pm
content: https://www.bipm.org/en/countries/caand you refer on section 3i'm not the one who use theses terms, but there is differences, i simply wrote what happen in some of our cal labs other i dont knowI ship over 10K $$ of stuff at a 1 or 2 year intervals and they clearly state, is it a certification or a calibration ?A certification can be issued without a calibrationI repeatIf after the certification you want to do a calibration, you can it's your choice if it goes well or not, because there may or was possible problems, they can or could be resolved by a calibration, if say: you have a failed range, the calibration get an incomplete status and it is not considered fully calibrated therefore it still get some failed status in the paperwork, it as i said it will be recordedAfter some repairs if it's possible, you can retry a calibration ... or not, bit it was already logged as having one problemI'm not talking about Keysight labs, there are others in Canada, Quebec city, Montreal, Ontario etc ...Some of my Gossens meter had to be shipped very far to be kept under the DAKKS system, some of my 34401 at the time (one was fully calibrated) the others where certified, and theses old 20 years pup where still in the ranges ...some scopes where calibrated, others not ... old tds220, tds 2k seriesEven some Cal labs have problems to deal with old thanks like TDS7254B and a TDS7404, have to ship them far away too'now shipping lots of brand new Siglent stuff we bough, and they will be "calibrated" because they work in critical stuffeven i i'm lost at word, it's some basic examples ... for sure it is contestable if some wants toeven some crappy (but working well) 3x bought juntek jds2900 at 100$ usd had been certified for 160CAD x3 ?? witch is a pure joke, i've done some battle with the certification guy, he simply dont care, i said its not worth it

author: alm
author_rank: Super Contributor
timestamp: December 31, 2023, 05:07:08 pm
content: Quote from: coromonadalix on December 31, 2023, 04:58:53 pmPlease do not repeat such misleading usage. It's internationally agreed (for example in the document I referred to) that calibration is a documented measurement or comparison, and adjustment of an instrument is called adjustment. You can ask for calibration with or without adjustment. For some instruments asking for calibration may also get you adjustment. See for example this video:

author: coromonadalix
author_rank: Super Contributor
timestamp: December 31, 2023, 05:41:18 pm
content: tell it to the cal labs we use ... they are the ones who scrap the good terminology / definitions etc ... and yes i can do bad telling it hereif they are wrong from the startsadly some and "i include myself", dont talk like thishere calibration is not a certification for sure, and calibration as the same usage as adjustment (the moment you change a reference value into an instrument)even got a big red / white sticker once on a psu "No Calibration needed" and i could still use itand some other Canadians can or could disagree toobut i'm not here to start a war of words, if i stepped on a land mine thats all boom lollwell return to the main topics as a mod would kindly ask