RANT - Buying a 3458A why is that hard? - Page 1
Forum section: electronics / general

author: mimmus78
author_rank: Unknown
timestamp: November 25, 2016, 08:36:12 pm
content: I went to town to buy a 3458A but I couldn't imagine that it could be so difficult.I can understand the average "ebay" seller but also the big players seems to ignore concepts like:- machine manufacturing date- short term drift issue- cal ram batteries replacement plan- calibration historyIn a few days I got some very genial replies:- "I don't know how old is the meter" when there is an HP logo on it- "cal ram is working properly"- "if meter passed calibration it meets its specifications included short term drift"- "I can offer traceable cal (without measurement uncertainties) included in this price."- "We can calibrate only up to 7 digits not 7.5"Really the level of the qualified T&M equipment dealers is this?Last one was from when I was asking for calibration of my just repaired K2001, thought it worthmentioning too as this coming from a cal lab is the most genial of all.Anyone knows where I can buy one of this meter from someone knowing what is selling?

author: pelule
author_rank: Frequent Contributor
timestamp: November 25, 2016, 09:13:33 pm
content: I would recommend Keysight, if you like to have security on the status.But you need the required budget for it.Unfortunately "cheap" and "good condition" do not match by default.Buying such a high precision DMM used means to take a certain risk in any case. And the risk increases, as cheaper it is offered.Just take a look to TiN's "used" gears and the efforts he put in to get it back to a proper condition.

author: rastro
author_rank: Frequent Contributor
timestamp: November 25, 2016, 09:35:16 pm
content: You may want to join the yahoo hp/agilent equipment group and post a WTB 'Want To Buy' for a 3458A.https://groups.yahoo.com/neo/groups/hp_agilent_equipment/info

author: mimmus78
author_rank: Unknown
timestamp: November 25, 2016, 09:39:17 pm
content: Keysight asked me a reasonable price for an almost new unit not that much higher than the one selling on eBay.Everyone is on a budget, but you are a dealer and asking me for almost 50% the price of a new one when it's a 20 Y old unit that you don't even have an idea if is ok or not is not fair.Inviato dal mio Nexus 6P utilizzando Tapatalk

author: HighVoltage
author_rank: Super Contributor
timestamp: November 25, 2016, 09:54:04 pm
content: It took me almost 2 years to find the right one and I don't know how many hundreds of mailsI finally found one and was very lucky to get a good onehttps://www.eevblog.com/forum/testgear/agilent-3458a-gpib-data-aquisition-software-and-options/msg1043469/#msg1043469You have to be patient or spend a little more and get one from the manufacturer with warranty.

author: Assafl
author_rank: Frequent Contributor
timestamp: November 25, 2016, 10:54:16 pm
content: I frequent such a place that sells old T&M equipment on eBay. A huge warehouse near Tel Aviv, their main business is taking apart PCs. They have a pile of motherboards about 1 - 1.5 meters high. They sell them.... There is a pile of hard disks. They sell those as well (whatever life they have left). DVD and CD ROMs in piles, laptops, batteries, etc. They also have studio equipment and microphones and reel to reel Studer boxes they sell for $800 (who buys these???).The outside walls are covered with piles of T&M. Piles of TDK-Lambda power supplies, of Aim-TTI power supplies. Racks and racks of boat anchor analyzers and scopes and time signal generators and broken optical equipment and comms analyzers losing value every day they are there. DMMs by the bucket (I "rescued" one) including tons of Tabor I guess he "scored" from a university lab somewhere and will never get rid of... I saw 2 GR digi bridges with notes in Russian as to why they are no longer working. A pallet box full of Agilent and Tektronix probes. lab equipment, stirrers, microscopes. etc. Old HP sine wave generators.What was millions in 1980-1990-2000 is waiting to melted for steel and silver and gold - unless he can make 100x selling it on eBay. He doesn't work hard. Sees a model number, types it in eBay. Sees the multitude of other (too expensive dealers) and brands a $399 price tag on an Aim-TTI triple power supply. I haggle and take it for yay under $200. 2 weeks ago he got a shipment of 20 more.But here is the bottom line: He has no clue what these things do. He does not know what an oscilloscope is or a signal analyzer. He does not know what installed options are and doesn't list them. He can't fix a blown fuse. He just writes "As Is for parts....". He powers it up and takes a picture using the iPhone.He sells T&M - but his business is extracting value from the scrapyard. Not selling T&M. He buys REALLY cheap (cheap enough so that he can even make a profit from the smelter) and sells what he can on eBay or to others like me to help the bottom line. My guess is most are like that (Better ones like Halted Specialties have a person test the T&M - but then the prices of the good stuff go even higher...).

author: razberik
author_rank: Frequent Contributor
timestamp: November 26, 2016, 12:07:42 am
content: So thats why a lot of T&M equip located in Israel is so dirty and smashed.

author: mimmus78
author_rank: Unknown
timestamp: November 26, 2016, 12:21:52 am
content: Assafi I can see the point but I ensure you the one that pronounced that phases are not supposed to be just eBay seller.Inviato dal mio Nexus 6P utilizzando Tapatalk

author: Assafl
author_rank: Frequent Contributor
timestamp: November 26, 2016, 06:35:38 am
content: Quote from: razberik on November 26, 2016, 12:07:42 amThat is a bit unfair. The DMM I got was practically new. Some of the stuff was never used. The AimTTi had yellowed knobs and a GPIB address sticker on it. Almost new otherwise. Right on spec as well.Problem was you couldn't tell from the photos or from the As Is warnings on eBay.Stuff from universities usuallly suck - especially if from the general EE101 labs. Abused hard over years. Oh those Tektronix can take abuse.The stuff from the research labs are hit miss. I used to lug HP and B&K out to sea on tug boats for navy experiments. I would probably buy those but the ones that go to artillary experiments I'd stay away from.What one really wants is a piece of T&M from a development lab with a Robert Pease type occasionally breadboarding topologies he is testing. Or even better - units purchased as backup in case the beaten up one fails.There are at least 10 of these places in Israel which means there is a whole lot of used T&M here. He lists maybe 1% of what he has. Probably less - which is a shame.

author: Assafl
author_rank: Frequent Contributor
timestamp: November 26, 2016, 07:00:40 am
content: Quote from: mimmus78 on November 26, 2016, 12:21:52 amThe only reason it works for them is that for a piece you pay 300$ for they paid 20$. As a single piece from a lot of 100's they buy from companies and universities.He pays a price as well: Had he known how to test the gear (and take better more meaningful photos) he'd close at a higher cadence and at a higher average price. But that isn't his model.Look at the DVC8500 calibrator on eBay. Most sell at around 100$. But there are on average 5-10 sellers trying to sell for 350-1000 dollars. One sold for that kind of price recently. That is what as a business he is looking for. A few sales like this out of a lot and he cashed back on the lot purchase. The model sucks for us but works for him.The moral of the story is find a local one, tour, and bring cash. Cash is king and you can shave 50-70% in person. Flaunt your cash like a pimp. It is hard for them to say "no".

author: TiN
author_rank: Super Contributor
timestamp: November 26, 2016, 07:14:38 am
content: Honestly, I think expecting ebay sellers who list 100s of T&M and whatnot items weekly to know and give details on very niche instrument like 3458A is a bit naive. Yes, there are few who actually know what they sell (one who often sells boards tested with upside down 3458), but they will also take more your money happily. These guys usually cured voltnuts or voltnuts in remission. There are so many quirks in hiend equipment, that would require weeks of expensive gear testing just to tell you one sentence "meter does not drift". Rare seller cares that much. Same goes to RF stuff I believe.Manufacturing date? Does it really matter? If its old, replace caps and enjoy aged meter.Calroms? Must be replaced, backedup and recalibrated anyway, why bother seller with it?Actually worst gear usually comes from folks who like to tinker or DIY repair, but lack of proper tools and knowledge to do so. All of us saw it - wrong parts bodged in, jump wires, etc

author: TiN
author_rank: Super Contributor
timestamp: November 26, 2016, 08:16:14 am
content: I agree on blueskull statement. There is no cheap 8.5 meters. Even if you get 3458A for free, you will end up buying 732B, SR104, teflon cables and 25$ binding posts just like that.At least calibration on 3458 is "easy", given you have 4ppm 10V and 8ppm 10Kohm and don't care for high frequency AC. Any other meter will need love from 5700/5725 or 4808 to get calibrated, which are rare exceptions in enthusiast labs.FlinstoneUnless you have good proof, I'd not say old HP-made 3458 from 1990 has any compatibility items with KS made is 2015. So saying boards not compatible is not correct. Even redesigned A5 with snaphat NVRAMs is just equal functionally redesign with same CPU but moved glue togic into Xilinx FPGA.

author: pelule
author_rank: Frequent Contributor
timestamp: November 26, 2016, 11:42:43 am
content: I do not expect many idiot out there, having the technical know-how to understand a quality and condition of a tool, but having no glue, what is the price for.So I am still not able to find the "critical point" here.If you want to buy a high precision 8.5 digit DMM (as already stated), you have two options:- option 1: take a lot of money in the hand and buy one with proofed condition from a proofed source (like Keysight)(if a seller is able to confirm/guarantee the condition, he will be able also to judge the price. or you shouldn't trust him).- option 2: having the specific know-how and the special equipment to check & repair.(the only way to proof the condition of a 8.5 digit DMM is to test it with >= 8.5 digit precise/stable equipment.that is not for free - its a prior investments and you expect a "return of that investment" in some way.If you don't have the know-how and right equipment, you NEVER will be sure, if the tool works correct.)It is the same, if you like to have a High Class car like a Porsche or Austin Martin- for a very good condition, you have to put a lot of money in your hand.- if you do not want to pay that lot, you will search for one with "not that good" condition, but having in mind, to put a lot of work in later.But you also need to have the know-how and the equipment to do the repair.Why is this should be different for a "High Class" equipment?

author: branadic
author_rank: Super Contributor
timestamp: November 26, 2016, 12:07:48 pm
content: I guess option 1 means a unit that has already been used? If so, option 3 is to buy a totally new unit. That's what we (our institute) did, we invested the money into a new Keysight 3458A with the additional options extended memory (option 001) and 4ppm/a (option 002) for our institute. I'm very happy about that.With some additional discount from the distributor and a discount promotion it was affordable. This could be an option for you, too. Find someone like an institute who gets discount from distributors and let them sell it to you without additional costs except taxes. They are happy to sell it without additional cost to you, as this increases their sales, but they are non-profit organisations. Got it?3458A: 8.395,00€Option 001: 604,00€Option 002: 1.180,00€ANSI Z540 Calibrationn: 309,00€-------------------------------------- discount+ taxes (19% in Germany)

author: Echo88
author_rank: Frequent Contributor
timestamp: November 26, 2016, 02:11:43 pm
content: Would you pay 9000€ for a hobby instrument branadic? I too dream of a 3458A, but this hobbyist dream is not worth 9000€.

author: mimmus78
author_rank: Unknown
timestamp: November 26, 2016, 06:04:53 pm
content: Quote from: pelule on November 26, 2016, 11:42:43 amThe problem is when you are a professional T&M equipment dealer, you are asking me 66% price of a new for a 20 years old crusty unit and you don't even have an idea if this meter is working or not. Everyone of this dealers declare the meters where refurbished, but in reality a good number of them just put power plug in the holes and maybe give it a run of self test.I'm paying a little extra not only because of your name, but especially for the service to have someone to check it and do the "programmed maintenance" on the instrument to ensure a good level of reliability. I'm buying this meter for many purposes and one of this is because I need it for work, if the meter stops because they forget to change cal ram batteries this will stop also my work and I don't like stupid things like this to happen.

author: ManateeMafia
author_rank: Frequent Contributor
timestamp: November 26, 2016, 06:20:56 pm
content: I am not sure about your local Keysight repair center but if your budget is 66% of a new unit, then "just" buy a broken but complete meter. Keysight will repair the meter and guarantee that it meets specifications. They will also change the NVRAM if they are old enough. Here in the US the price for repair is ~ $3K. After it is repaired, buy a service agreement for as long as it is offered. I got a 5yr agreement for mine.I don't think any service center or reseller has the capability to test this meter other than Keysight or a few extremely well equipped labs. Either way, Keysight has the parts so your options are limited.Also, contact Keysight for a possible refurbished model with a guarantee. They may have some available for resale at a price more reasonable than these other sellers.In the end, your final price with a guarantee may still cost almost 6K Euro.

author: branadic
author_rank: Super Contributor
timestamp: November 26, 2016, 06:55:24 pm
content: Quote from: Echo88 on November 26, 2016, 02:11:43 pmDo you buy cars? How much are they? Isn't that hobby too?But I don't need a 3458A in my homelab, as long as I have the possibility to use the unit at work. I'm happy with my Prema 5017 SC at home.

author: branadic
author_rank: Super Contributor
timestamp: November 26, 2016, 06:59:38 pm
content: Quote from: Flinstone on November 26, 2016, 03:11:27 pmSure, but we don't get dicount at Meilhaus, so all in all Datatec is cheaper (for us).

author: TiN
author_rank: Super Contributor
timestamp: November 27, 2016, 02:54:58 am
content: If your work pays off the cost of having 3458A (service plan + calibrations) then best way is to go right to the Keysight.Because any other options are not giving you any safety if your works depends on it. Let's say you even found and bought never used 3458A for 4000$, specified by seller as so, and passing all tests and stable. Ok, great deal, right?Then after 3 months of happy life ADC hybrid goes sick, and you are looking at instant 3900$ repair cost (new ADC board + calibration), with few weeks of downtime. So you pay 7900$, which still leaves you w/o warrantyNot such a sweet deal anymore, aye?I'd separate hobby use and pro use and make decisions accordinglyHaving myself 3458 I am ok to bear risks to have box w/o warranty, as I do calibration myself, and all non important stuff like bad calrom chips, old caps, busted panels are not worth the time to spend to ask seller. I can see enough on photos of the unit to commit or not. In worst case I'll have dead unit, which is bad, but that only means that some of hobby projects at home will need to wait, not the lost business revenues. My usual threshold for buying parts/broken units is usually no more than 20% of market price for good boxes. That means below 1k$ for 3458A, which are not very often deals on places like eBay.

author: Assafl
author_rank: Frequent Contributor
timestamp: November 27, 2016, 06:19:05 am
content: Quote from: TiN on November 27, 2016, 02:54:58 amThere are other scenarios. Like a manufacturing line that requires a certain device (fully programmed using Labview - as an example). If the existing device becomes rickety they may want to find another for cheap. They don't want a different device since they will have to reprogram and decertify their line. Even if they only need 4 digits of an 8 digit device.Also, there is always the non exportable countries buying stuff. Not that the seller can know.

author: TiN
author_rank: Super Contributor
timestamp: November 27, 2016, 06:46:04 am
content: K2002 does not use special custom parts, and specs are more relaxed. I'd expect most want 3458 due to it's mighty ADC.AssaflSure, there are many folks looking at these units, including calibration labs and various naughty resellers, who think they sit on gold there.There is one 3458 for sale in local used T&M shop, with busted VFD and missing board. It was up for sale when i come in Taiwan 6 year ago, and still is. I offerred 1300$ to seller few months ago , he said no less than 2k. And front panel from KS is close at 1k alone. So I wished good luck and got one off ebay <1k.

author: mimmus78
author_rank: Unknown
timestamp: November 27, 2016, 09:55:50 am
content: TiN there is "repair per incident" that is "just" 2300 USD so you are not going to spend others 4000 for any repair.Even in business you don't have unlimited budget and all you spend must produce a ROI. This is especially true if you are very small.Anyway my rant is about some T&M dealers that ask premium price (at same level of Keysight) but they do way worse service than any volt aficionados can do.Inviato dal mio Nexus 6P utilizzando Tapatalk

author: mimmus78
author_rank: Unknown
timestamp: November 27, 2016, 10:10:51 am
content: Yesterday I received an offer from a dealer in the same ballpark of the other dealers I contacted.He explained precisely what was his refurbishment check list before he sell this instrument, this includes also an A3 assembly replacement, cal ram replacement with data preservation (if available) and details on procedure and instruments used for calibration.This is what I was searching when dealing with dealers but I was deftly too naive to pretend that.Inviato dal mio Nexus 6P utilizzando Tapatalk

author: HighVoltage
author_rank: Super Contributor
timestamp: November 27, 2016, 10:11:50 am
content: FlinstoneMost likely Keithley, Fluke and Transmille have reworked their units to be RoHS compatible?Otherwise it would not make any senseBut who knows, may be Keysight as a new 8 1/2 digit meter ready?The guy that does my official calibrations claims that the older HP units are much more stable because of those ceramic chips.May be we should put an older and a newer model next to each other and compare?

author: TiN
author_rank: Super Contributor
timestamp: November 27, 2016, 12:54:30 pm
content: Quote from: mimmus78 on November 27, 2016, 09:55:50 amRepair usually does not include calibration, which is in case of A3 board replacement is required. Of course, one can go with regular calibration, which is much cheaper than standards one for ~2.5k, so there are options for any requirements.QuoteSure, that's why I said cost of ownership meter like 3458A, rather than price of having the box. Just after few years of use and maintenance, cost of calibrations alone will exceed MSRP of meter itself.HighVoltageQuoteThis is case which needs a photo first , too see those magical ceramic parts. Reader's unit I was fixing recently was the oldest I ever saw, 1989-1990 parts with SN 04xxx, and yet it uses all the same plastic opamps as ones made in 00's.So before we speculate any more, let's get solid info what is different. So far even photo of newest A3 2015 year from KS site shows same ceramic ADC hybrid and plastic opamps around.Old units are likely more stable just due to aged parts and reference.CAL?72 test shows only ADC stability. Meter still can have other issues/drifts on other functions/ranges, but show perfect CAL?72 data.

author: mimmus78
author_rank: Unknown
timestamp: November 27, 2016, 01:11:29 pm
content: TiN this "repair per incident" includes also calibration to upper standards. After this official refurbishment you can also apply to warranty agreement for few hundred bucks per year.Anyway I actually need more the stability than absolute accuracy. I'm building 3 or 4 LTZ1000 references and I will send the best to be calibrated. I'm also planning to buy a 10k entry level standard resistors or some of this ultrastable Vishay "cans resistors" that where proven to drift only fraction of ppm per year.This will be fair enough for what I need in my business, and it will also cure my volt nutting needs for some time.I don't even need AC calibration as it's only needed for high frequency > 100kHz and for me 30kHz is more than enough.I prefer to spend this other 4000 Eur to buy other equipment that can verify the meter than just the thing.

author: Andreas
author_rank: Super Contributor
timestamp: November 27, 2016, 07:13:25 pm
content: Quote from: mimmus78 on November 27, 2016, 01:11:29 pmYou have a "man with 2 clocks" problem:How can you determine wether the HP3458A reference (LTZ1000) or your built referencesdrift faster (usually in the same direction).The only way out is a Fluke 732B with frequent calibrations.But in this case you might not need a further LTZ1000 reference to be calibrated.Or the other way round:If you cannot tell which of your 4-5 (including the HP3458A) references really drifts the leastyou could also take the difference voltages between the LTZ1000 references (in 100mV range)with a much cheaper (6.5 Digit) instrument.You will only need 2 additional calibration points of one of the LTZ1000 references to determine the best.With best regardsAndreas

author: mimmus78
author_rank: Unknown
timestamp: November 27, 2016, 09:25:41 pm
content: Andreas:as I write before I don't need absolute accuracy to ppm as 50 pmm will be more than adequate to check calibrationof instruments I sell. I know for this I can also use the 6.5 digits meter, but nobody can ensure me that all the rangeswill stay in specs for the needed time on this type of instruments.A 3458A is not only capable of calibrate itself but in doing this you can also monitor calibration constants of eachrange and spot any excessive drift from last autocal. If you find excessive drift somewhere you canusuallyteardown the instrument, find what's happening and eventually fix it.So my plan is initially to use this 4 LTZ1000 just to check with a reasonable confidence that the 3458A is notdrifting too much. Than I hope to find at least one reference that I trust enough so that I can send it some cal lab (orsomeone I trust) for calibration and import this 7V with a reasonable uncertainty to my lab.As for the 10K I think it is more easier as any calibrated Vishay VHP202 or VHA518-7 will be more than enough forindirect checking that this 40K resistor inside the 3458A has not drifted too much. Those resistor have proven 2ppmx 6 years drift, it wouldn't be so much hard in a second time to characterise a couple of this resistors for temperatureand use this as entry level standard. Even with a drift of 3ppm per 6 years I will be good for more than a decade.I know this is quite excessive for my requirements but this is a quite enjoyable path too.

author: TiN
author_rank: Super Contributor
timestamp: November 28, 2016, 02:00:55 am
content: That's almost the very path I went year ago with my rusty 3458.QuoteSo we will soon to see pics of new toy at your home?

author: plesa
author_rank: Frequent Contributor
timestamp: November 28, 2016, 02:27:33 am
content: Quote from: mimmus78 on November 27, 2016, 09:25:41 pmIt doe not look like you needs 3458A, but it is quite good meter.Before buying used one, check it can run over 24h on NPLC >10, this can highlight convergence errors ( A3 replacement )Ask seller to enter CAL? 2941 from front panel - overloads counter.

author: razberik
author_rank: Frequent Contributor
timestamp: November 28, 2016, 08:41:11 am
content: Quote from: TiN on November 27, 2016, 12:54:30 pmThats questions me, for what anybody need the 3458A for when he dont use its capabilities ?I wonder how many 3458A are out there for hobby use like storing it for the feeling of "just owning it".I dont say I am different, I want 3458A too because it is a King of All Multimeters. I dont really need it, but Iwantit.

author: TiN
author_rank: Super Contributor
timestamp: November 28, 2016, 08:55:09 am
content: Having 3458 sitting idle is a voltnut crimeMine almost always logging Vrefs or resistors , even if I'm out of the city, like now.

author: HighVoltage
author_rank: Super Contributor
timestamp: November 28, 2016, 10:08:03 am
content: I have my 3458A for about a month now and it has been running and measuring something every day.It is finally something that I can rely on and compare my other multimeters against.And I finally know for sure, how bad the 34401A is in comparison in the low ppm range.

author: tszaboo
author_rank: Super Contributor
timestamp: November 28, 2016, 02:56:22 pm
content: Quote from: HighVoltage on November 27, 2016, 10:11:50 amI specifically asked an engineer from Agilent on the electronica show about an upcoming new 8.5 digit meter. He said, that they have issues, that they dont make anymore accurate analog parts. As far as I understand, they dont have anything comparable in development, not in the near future anyway.Quite sad, if you ask me. Would have loved to see what they can do with new components.

author: mimmus78
author_rank: Unknown
timestamp: November 28, 2016, 04:13:58 pm
content: @plesa"CAL? 2941" interesting but what number is safe? I suppose 0 ... than even if 1 shows up how can you assume it was a very dangerous or not?I don't know if this can be a "realiable" parameter to check the meter.Maybe is more useful to ask seller to do autocal, wait some days (7 will be the best) redo autocal and than check drift of all calibration variables.Anyone has ever produced typical drift for all calibration variables?>> Before buying used one, check it can run over 24h on NPLC >10, this can highlight convergence errors ( A3 replacement )On the service note they say to test drift for one week and than divide by 7 to get an average value ppm x day.

author: mimmus78
author_rank: Unknown
timestamp: November 28, 2016, 04:24:33 pm
content: @ TiN>> That's almost the very path I went year ago with my rusty 3458.Hope I don't end up buying a 57X0 in a year :-)>> So we will soon to see pics of new toy at your home?It seems more likely. It will be not as cheap as one can imagine, but still with a reasonable price and with its replaced new A3 board I should be covered for the most scaring problem it may have.

author: plesa
author_rank: Frequent Contributor
timestamp: November 28, 2016, 05:31:31 pm
content: Quote from: mimmus78 on November 28, 2016, 04:13:58 pmFor me it is 0 = OK, !=0 possible problems. All parameter including this one will give you more information about unit. Check also calibration string CALSTR?, cal labs store there last calibration date.You do not needs to run whole acal, just ACAL DCV and check the CAL? 72 value, similar for ACAL OHMS.You mixed together two things, drift and convergence errors. For convergence errors, just keep meter running over 24h on higher NPLC, it is more probable that convergence error will occur than on fast NPLC settings. The drift is monitoring of CAL? 72 value over time after ACAL DCV.Did you asked Keysight remarketed/premium used guys for 3458A?BTW check thishttp://www.gellerlabs.com/HP%203458A%20DMM.htm

author: CalMachine
author_rank: Frequent Contributor
timestamp: November 29, 2016, 02:10:53 am
content: If you purchase one that you're sketched out with, you can send it to me and I'll give it a legit 17025 accredited cal with uncertainties for a fair price! If you get one off ebay and it comes as-is with issues, I can also get some repairs done.Also, generally the older HP labeled 3458A's are better than Agilent or Keysight. They were made with higher quality references and are more stable.... as long as they've been used. If they've been powered off for any significant periods of time, it could take months for the stability to be achieved.

author: HighVoltage
author_rank: Super Contributor
timestamp: November 29, 2016, 08:34:25 am
content: Quote from: CalMachine on November 29, 2016, 02:10:53 amCalMachineCan you be more specific in regards to what components really were better on the older models?

author: mimmus78
author_rank: Unknown
timestamp: November 29, 2016, 09:28:37 am
content: @plesa:My unit will have new A3 board from Keysight and it will be covered by official warranty so I don't think I have to worry of short term drift problems for now.I will have one mount of warranty for all the unit and this is plenty of time to check everything and considering I also own a multifuction calibrator my first project will be to check it in all ranges.As for "CAL? 2941" let say I would be happy if is zero, OK if is a small number. If is a reasonable bigger number I need to study what this really means ...@CalMachineAnyway based on serial number my unit will be one of last unit made by HP before they become "another company" ... and hope to get the very best aged components (that fails more often).I still think that a 5yo unit is the optimal, who really cares if drift 3ppm instead of 1ppm in a year (and if you really care, you still need to calibrate it).

author: CalMachine
author_rank: Frequent Contributor
timestamp: November 29, 2016, 01:41:09 pm
content: Quote from: HighVoltage on November 29, 2016, 08:34:25 amUsually its the voltage reference board. That's where most of the stability comes from. You can see service notes put out by agilent and perhaps even keysight regarding unstable voltage references. This was almost never an issue with HP labeled 3458As. I've only been in the field for almost 3 years now, but this is what I have experienced and learned through the contacts I've made.Quote from: mimmus78 on November 29, 2016, 09:28:37 amYeah aged units are always going to have a higher probability of having a failing component. However, I feel like having the longer proven stable voltage reference would be more sought after, though. If you don't need 1 ppm or lower drift, then for sure, any 3458A will work just fine.

author: mimmus78
author_rank: Unknown
timestamp: November 29, 2016, 02:32:37 pm
content: Don't tell me ...I brought a K2000 and a K2001 for parts. K2001 had a problem in an analogue switch in current measurement circuit (few hours of work to repair it).K2000 I had to replace the ASIC from a donor unit because a "GPIO" was dead (here I spent a lot of time trying to fix it because I didn't wanted to change the ASIC and trying the most esoteric stuff that at the end didn't worked).30 days agoo K2001 failed again: found an analogue switch was leaky. This time on the current source for ohm measurement. This required other 10 hours of work to fix it (and calibration lost in high ohm ranges was for free).In the mean time on K2000 a diode bridge went wonky causing it to go crazy after 60 minutes of use.I repaired it again (this time it was 5 minutes of work) and after I run self test I discover that is has also others small problems (didn't have yet time to check).I hope to be more fortunate with this 20 years meter ... how was your experience with the 20 yo boys?

author: pelule
author_rank: Frequent Contributor
timestamp: November 29, 2016, 07:40:12 pm
content: QuoteA really bad experiance. "Sometimes you have no luck and misfortune in addition."I repaired my Datron 1281 (build in 1988) ~three years ago and is working without any problem since that time.My HP3458A (build in 1989) I bought two years ago and is also working properly.I assume both have well aged references.

author: plesa
author_rank: Frequent Contributor
timestamp: November 29, 2016, 07:52:06 pm
content: Quote from: mimmus78 on November 29, 2016, 09:28:37 amOKI, new A3 is good but if you purchase it from Keysigh it is not tested, also do not forget to check the A5 version. Because if seller is going to invest into new A3 and there is old A5 the investment is close to Keysight repair agreement 2k USD/2.8k USD ( which contains calibration report).

author: mimmus78
author_rank: Unknown
timestamp: November 30, 2016, 12:01:13 am
content: Plesa I didn't understand what you are trying to tell me. The A5 is the one with batteries? He will replace those chips and if they are still alive also data will be preserved.Inviato dal mio Nexus 6P utilizzando Tapatalk

author: mimmus78
author_rank: Unknown
timestamp: December 01, 2016, 10:50:43 am
content: Interesting ... directly from 3458A manual ->DEFEAT ONdisables (defeats) the input switch sequencing that protects themultimeter's input circuitry from overload voltages. If inputprotection is disabled and an overload situation is detected onthe 10V range or below, the multimeter will enable inputprotection and internally tally the overload for instrumentwarranty considerations.

author: Alex Nikitin
author_rank: Super Contributor
timestamp: December 01, 2016, 11:54:44 am
content: Quote from: mimmus78 on December 01, 2016, 10:50:43 amWell, I don't know the history of our 3458A, CAL?2941 returns 1505, however I don't have any problems with it, Keysight did calibrate it and put it on a 3-year service agreement without any comments.CheersAlex

author: mimmus78
author_rank: Unknown
timestamp: December 01, 2016, 11:57:25 am
content: Wow 4 digits!!! I imagine is kinda of World Record!Inviato dal mio Nexus 6P utilizzando Tapatalk

author: Lowpass30Hz
author_rank: Newbie
timestamp: December 05, 2016, 05:13:00 pm
content: Quote from: Flinstone on November 27, 2016, 05:56:56 amThat is exactly correct. Keysight is not updating the 3458A to be EU RoHS compliant. They will no longer sell one with a final destination inside the EU.It is still fully supported, I imagine for a long time in to the future.

author: Macbeth
author_rank: Super Contributor
timestamp: December 05, 2016, 07:46:42 pm
content: Quote from: Lowpass30Hz on December 05, 2016, 05:13:00 pmInsanity. Even when these meters are totally decommissioned, some poor child scavenging dumps in the Philippines or somewhere resurrects them and passes them on to a junkyard operator who then gives the kid a few lollipops and recycles them to some other middleman and then on to ebay. So the dangerous "Hazardous Substance" (leaded solder) all come back to haunt the EU no matter what. In the most miniscule amount possible.Sadly I think despite #Brexit these meters will still be banned from direct sale in the UK. Precisely because the sale of them is so minuscule as to not even warrant a change in legislation.Then again Trump has UK "at the front of the queue", unlike Obamas "back of the queue" and maybe Keysight being american can influence this?

author: mimmus78
author_rank: Unknown
timestamp: December 05, 2016, 10:33:07 pm
content: When I speak with some Microlease guy few weeks ago (they are the one to call if you want a 3458A new in Italy) they told me that there was this problem, but they didn't told me that this instrument will be "banned" for sure ... they just didn't know yet what was the strategy. Anyway I think ROHS directive allow some authorised exceptions and this will probably be the way to shortcut the problem.

author: rastro
author_rank: Frequent Contributor
timestamp: December 05, 2016, 11:06:53 pm
content: I wonder if they could sell them in kit form.Then someone else could deal with the compliance of politically correct solder.

author: Messtechniker
author_rank: Frequent Contributor
timestamp: December 06, 2016, 01:56:28 pm
content: Quote from: mimmus78 on December 05, 2016, 10:33:07 pmNon-ROHS compliant equipment, (i.e. lead in components and lead in solder) is allowed in the EU for military and medicinal applications.So if you run the right kind of company ....Yours Messtechniker

author: TheSteve
author_rank: Unknown
timestamp: December 24, 2016, 02:12:34 am
content: Anyone up for a challenge?http://www.ebay.com/itm/112246180384http://www.ebay.com/itm/112246269329

author: guenthert
author_rank: Frequent Contributor
timestamp: December 24, 2016, 05:21:43 am
content: Quote from: TheSteve on December 24, 2016, 02:12:34 amI'm not in the market (need to keep my pennies together and so far my 3456a entertains me well enough), but still I enjoy the show. I hope some expert technician gets it and makes a repair blog.

author: TiN
author_rank: Super Contributor
timestamp: December 24, 2016, 08:34:55 am
content: I had enough bad luck with A3 replacements, so I'll pass on these units number 3 and 4

author: mimmus78
author_rank: Unknown
timestamp: December 24, 2016, 11:44:14 am
content: You'll can never have enough 8.5 digits multimeters. Are you sure?

author: mimmus78
author_rank: Unknown
timestamp: December 24, 2016, 11:49:09 am
content: Ohhh I realised. Someone should have hacked TiN account. Those ain't his words!Inviato dal mio Nexus 6P utilizzando Tapatalk

author: Echo88
author_rank: Frequent Contributor
timestamp: December 24, 2016, 10:09:01 pm
content: Living in Germany and seeing those repairable 3458As being auctioned off in the USA only, with no shipping to Germany, brings a tear to my eye. Seems like i will never get a fully working one for <3k.

author: Theboel
author_rank: Frequent Contributor
timestamp: December 25, 2016, 12:32:50 am
content: Hi All,What about Japan auction site ?something like this :http://buyee.jp/item/yahoo/auction/k234851443?lang=en&rc=yauccafter shipment I believe still under 3K USD

author: guenthert
author_rank: Frequent Contributor
timestamp: December 25, 2016, 06:49:03 pm
content: Quote from: Echo88 on December 24, 2016, 10:09:01 pmRepairable? Perhaps. We don't know the history of those units. Did the banged up just fell of the a rack, smashing the display lens or did that happen first and then was used to swap parts with other units which aged out of tolerance? A working 3458a in a banged up chassis would be great, a drifting, not calibrated, not be able to be calibrated one in a banged up chassis isn't. Quite a gamble.

author: Echo88
author_rank: Frequent Contributor
timestamp: December 27, 2016, 05:21:48 pm
content: As im comparing the prices on various ebay-sites(.com,.it,.fr,.co.uk,.de) im coming to the conclusion that used 3458As are available for not much less than 4k at the moment (including tax/vat from the usa to germany). Time to reach out for other marketplaces.

author: mimmus78
author_rank: Unknown
timestamp: December 27, 2016, 10:11:43 pm
content: Yes ebay is not the right place to buy one of this beast ... unless you what to go the TiN way.

author: Echo88
author_rank: Frequent Contributor
timestamp: December 27, 2016, 10:20:39 pm
content: Where did you get yours?

author: Robert763
author_rank: Super Contributor
timestamp: December 31, 2016, 11:08:52 pm
content: Arguably the RoHS regulations don't apply to the 3458A. There are two grounds for this. Firstly it was first placed on the market before 2006. Secondly and more importantly, a DMM does not actually fit into any of the categories of equipment the regulations apply to. At leas according to UK official guidancehttps://www.gov.uk/government/uploads/system/uploads/attachment_data/file/31803/11-526-rohs-regulations-government-guidance-notes.pdfFor other EU regulations it would be considered measuring or labaoratory equipment, neither of which are mentioned in the RoHS guidance. A loophole? Maybe but the quantiites are so low it's immaterial.The requlations only apply to new equipment so an alternative work-around would be to by an ex-rental unit from North America.

author: TheSteve
author_rank: Unknown
timestamp: December 31, 2016, 11:35:22 pm
content: Quote from: mimmus78 on December 27, 2016, 10:11:43 pmIf you're a business that needs a 3458A right away then a new one from a retailer is the way to go, if you're a home nut or a business that can wait for a good looking unit then ebay totally rocks as a place to buy one.editAnd another one was just listed - this one has an isolator failure. It isn't buy it now though so the price will be bid way too high.

author: plesa
author_rank: Frequent Contributor
timestamp: January 01, 2017, 11:30:48 am
content: Quote from: Flinstone on January 01, 2017, 11:26:32 amHappy new yearWhat is strange, that the SN sticker is missing. Without serial will be difficult to track history of unit. Unit looks like new, so maybe it can be covered by warranty.

author: HighVoltage
author_rank: Super Contributor
timestamp: January 01, 2017, 12:09:58 pm
content: Quote from: mimmus78 on December 27, 2016, 10:11:43 pmHappy new year to all of you.I found my "almost new" 3458A on ebay and I am totally happy with it.If you take the time to look around and ask the seller lots of questions, eventually you will find a good one.But the restrictions of 2017 will probably change all of that.So, I am happy to have a good working one.Also, it might be difficult, starting today, to get a used one imported in to the EU.Only time will tell

author: HighVoltage
author_rank: Super Contributor
timestamp: January 01, 2017, 12:12:58 pm
content: Quote from: plesa on January 01, 2017, 11:30:48 amThis meter was one that I tried to buy from the seller.But he never responded to my questions about the missing sticker.Something is not right about this meter or the seller, I think.

author: plesa
author_rank: Frequent Contributor
timestamp: January 01, 2017, 12:18:49 pm
content: Quote from: HighVoltage on January 01, 2017, 12:12:58 pmMaybe, that's the reason why unit is on eBay for long time. Strange is that some units looks like sold and after few month there is new seller offering them again

author: saturnin
author_rank: Regular Contributor
timestamp: January 01, 2017, 02:38:51 pm
content: Happy new year to everybodyThe mentioned seller has received very negative/alarming feedback recently, so I would be very cautious in case of buying anything from him (and 3458A especially):http://feedback.ebay.com/ws/eBayISAPI.dll?ViewFeedback2&userid=bettyboopbii09&iid=262784479466&de=off&items=25&searchInterval=30&which=negative&interval=30&_trkparms=negative_30

author: HighVoltage
author_rank: Super Contributor
timestamp: January 01, 2017, 03:27:12 pm
content: Quote from: saturnin on January 01, 2017, 02:38:51 pmGood catch, I had not even noticed that.And some items he sold are not cheap.This seller has a pattern of very bad feedback.

author: mimmus78
author_rank: Unknown
timestamp: January 01, 2017, 05:26:21 pm
content: Four negative feedbacks is a no no. You must act very badly to get such high number of negative feedbacks. This is professional stuff ... no cheap 1 EUR things, you will not receive negative feedbacks selling this stuff if you really don't deserve it.

author: HighVoltage
author_rank: Super Contributor
timestamp: January 02, 2017, 11:29:47 am
content: One just showed up on ebay Germany:http://www.ebay.de/itm/152378840725HP branded 3458A for Euro 5000It seems the expected price is already rising.

author: mimmus78
author_rank: Unknown
timestamp: January 03, 2017, 02:48:47 am
content: Quote from: HighVoltage on January 02, 2017, 11:29:47 amJust listing doesn't make a price. This was the same price microlease (the Italian keysight distributor) quoted me few months ago.Inviato dal mio Nexus 6P utilizzando Tapatalk

author: mimmus78
author_rank: Unknown
timestamp: January 03, 2017, 02:53:46 am
content: What is your dt (internal vs external temperature)? My unit go up 16°C over the ambient temperature.Inviato dal mio Nexus 6P utilizzando Tapatalk

author: TheSteve
author_rank: Unknown
timestamp: January 03, 2017, 03:32:05 am
content: Both of mine are 11-12 degrees over ambient, they have very good airflow around them.

author: acbern
author_rank: Frequent Contributor
timestamp: January 03, 2017, 07:41:40 am
content: One of mine I just checked is about 14K above Tamb. It uses the newer fan filter, which I would think has a better air throughput than the earlier fine mesh filters.

author: TheSteve
author_rank: Unknown
timestamp: January 03, 2017, 08:02:48 am
content: I would think the original filter has less restriction then the newer filter as long as it is kept clean - the holes aren't that small in it and you can easily see through through it. I'm no expert on filters though.

author: HighVoltage
author_rank: Super Contributor
timestamp: January 03, 2017, 08:58:53 am
content: Mine is about 14 degrees above environment

author: VK5RC
author_rank: Unknown
timestamp: January 03, 2017, 10:37:01 am
content: +14

author: Alex Nikitin
author_rank: Super Contributor
timestamp: January 03, 2017, 10:44:22 am
content: About +12C right now but could be up to +14C if the filter is not very clean. Usually I clean the filter when the difference is about 14C and it drops the temperature back to +12C from the ambient.CheersAlex

author: TiN
author_rank: Super Contributor
timestamp: January 03, 2017, 12:19:23 pm
content: I have no filter on mine.+10-11C delta.

author: mimmus78
author_rank: Unknown
timestamp: January 03, 2017, 12:22:11 pm
content: If air is going out I think filter is only for to avoid some bug visit our multimeter ... better not remove it. Guess anyway I have to check if was clean during refurbishment.Inviato dal mio Nexus 6P utilizzando Tapatalk

author: TiN
author_rank: Super Contributor
timestamp: January 03, 2017, 02:02:27 pm
content: Air going in.Since my meter is 24/7 on, any possible bugs would be quickly and surely disassembled upon arrival. That 25mm thick Delta fan does not welcome foreigners..

author: mimmus78
author_rank: Unknown
timestamp: January 03, 2017, 02:14:03 pm
content: Ouch yes air is going in. Read somewhere else that was expelled. Anyway I had meter attached to the wall on a side, this was obstructing one side air outlet. Now with filter clean and some more space on a side it's 13.Inviato dal mio Nexus 6P utilizzando Tapatalk

author: mimmus78
author_rank: Unknown
timestamp: January 03, 2017, 02:20:53 pm
content: Wondering if there is a way to modulate fan speed based on ambient temperature. This will help keep temperature more stable.But than we have the problem that when speed is slow there will be more temperature gradient inside the meter.So even if done who can prove things get better? You need a 3458a into a thermal chamber a do calibration verification every few degrees.Inviato dal mio Nexus 6P utilizzando Tapatalk

author: Dr. Frank
author_rank: Super Contributor
timestamp: January 03, 2017, 03:15:55 pm
content: Quote from: mimmus78 on January 03, 2017, 02:20:53 pmThat is:.. or more politely, it's the wrong approach..It's well known, that the 3458A definitely has to be used in a temperature stable, laboratory grade environment, say about 23°C +/-2°C nominal and +/-0.2°C change during the run of your experiments.Only then, you will get reproducible and stable measurements.The specified T.C.s for the different modes and ranges will tell, what you might expect, with ACAL, and w/o.It's a fact, that with ACAL, DCV has about 0.15°ppm/C, and Ohms about 1.. 0.5ppm/C, as latter lacks an ovenized or compensated, or more tightly T.C.-selected 40k reference.The T.Cs w/o ACAL add about 0.5..2ppm/°C.These rough figures apply for mostly all other long range DMMs in a very comparable manner, as they all use more or less similar technologies and components.The Fluke 8508A only is much more stable wherever resistors are involved, especially on 1yr. stability spec., as it has to rely on this stability over one year, due to the lack of the 3458As ACAL feature.Anyhow, both instruments are in the same ballpark, and trying to additionally temperature stabilize their interior, is not the effective way.Again, all these instruments are in no way DCV or Ohm standards, exactly due to these described restrictions.So I propose, that you instead maintain external temperature stable DCV and Ohm standards, so that you can do stable absolute measurements.Frank

author: plesa
author_rank: Frequent Contributor
timestamp: January 03, 2017, 09:15:58 pm
content: Quote from: TiN on January 03, 2017, 12:19:23 pmclean filter 2nd generation, internal temperature 35 °C with ambient 24 °C. With ambient temperature span over 10 °C is internal temperature changed only by 5 °C.During this experiment is visible that DCV gain has negative tempco ( to be exact -0.2 ppm/°C ). DCV gain changed from 0.9933635 to 0.9933643.What is strange that during calibration was internal temperature 39 °C with ambient 23 °C, probably airflow was restricted.

author: mimmus78
author_rank: Unknown
timestamp: January 05, 2017, 04:30:42 pm
content: >> That is:.. or more politely, it's the wrong approach..Guess will be more easy to dig a hole into the garden to create a bunker ... suppose this last project will make both me and my wife more happier.

author: Dr. Frank
author_rank: Super Contributor
timestamp: January 05, 2017, 07:27:51 pm
content: Quote from: mimmus78 on January 05, 2017, 04:30:42 pmIn Italy, don't all of your houses have nice cellars, for this well Italian wine, for example?That's the best location for constant temperature and the 3458A..Frank

author: dr.diesel
author_rank: Super Contributor
timestamp: January 05, 2017, 08:27:40 pm
content: One more addition to the group!

author: TheSteve
author_rank: Unknown
timestamp: January 05, 2017, 09:18:45 pm
content: Very nice! Was it perfect when you received it or did you need give it a little TLC?

author: dr.diesel
author_rank: Super Contributor
timestamp: January 05, 2017, 09:59:26 pm
content: Quote from: TheSteve on January 05, 2017, 09:18:45 pmUPS just dropped it off, perfect physical condition, but other than the seller stating it works, unknown.Bummer, looks like gpib is busted on mainline kernels and not just the rpi stuff, dangit.

author: ManateeMafia
author_rank: Frequent Contributor
timestamp: January 06, 2017, 02:06:05 am
content: They look great when clean and not busted to pieces.TiN and I have had good luck with the python libraries. At least you could grab some data for the next several days to determine the stability of that nice meter.

author: TiN
author_rank: Super Contributor
timestamp: January 06, 2017, 04:30:35 am
content: Based on recent acquisitions by mimmus, TheSteve, dr.diesel now, I think this thread title is very incorrect, as you guys getting these meters like mushrooms after the rain

author: plesa
author_rank: Frequent Contributor
timestamp: January 06, 2017, 06:02:41 am
content: Quote from: dr.diesel on January 05, 2017, 09:59:26 pmIt is still strange, version 4.0.3 is listed as tested on 4.5 kernel.Maybe if you have RPi1 you can try it, there is rumor that it works.Check the LogNuts thread for latest info.

author: TheSteve
author_rank: Unknown
timestamp: January 06, 2017, 06:26:12 am
content: Quote from: TiN on January 06, 2017, 04:30:35 amYou started the trend...

author: mimmus78
author_rank: Unknown
timestamp: January 06, 2017, 09:57:14 am
content: Dr. Frank yes usually we have it ... but it's hard that a bottle of wine find the way in the "cantina" before it's already empty (evaporated).Inviato dal mio Nexus 6P utilizzando Tapatalk

author: HighVoltage
author_rank: Super Contributor
timestamp: January 06, 2017, 01:29:22 pm
content: Congratulations Dr.Diesel to your new toy.I just talked to a German distributor of the 3458A and they said they will have plenty of meters left for the next two years to sell.They are still awaiting a shipment from Keysight in this month.

author: mimmus78
author_rank: Unknown
timestamp: January 06, 2017, 02:01:58 pm
content: Quote from: HighVoltage on January 06, 2017, 01:29:22 pmWell technically speaking ROHS apply to the items sold by the producer ... if some reseller has it on the shelf this doesn't apply.Inviato dal mio Nexus 6P utilizzando Tapatalk

author: bingo600
author_rank: Super Contributor
timestamp: January 06, 2017, 07:03:15 pm
content: Quote from: dr.diesel on January 05, 2017, 09:59:26 pmThe Agilent is working 100% in my Linux Mint 17.3 x64 - (Should be same kernel as on Ubuntu 14.04)QuoteAnd it's working on my Raspi v1 , with Noobs 1.41 , updated to the raspbian,org kernel (that won't work on a Raspi v3)/Bingo

author: mimmus78
author_rank: Unknown
timestamp: January 06, 2017, 07:37:59 pm
content: If is working on X86_64 I guess should be some endianes job ... can someone test on some other ARM processor?