SOLD: Many Keysight 34465a Multimeters under $700 - Page 1
Forum section: electronics / general

author: neverendingstudent
author_rank: Regular Contributor
timestamp: January 30, 2025, 10:40:05 pm
content: So, I found this guy through eBay - the link to the meters on eBay is here:https://www.ebay.com/itm/186915657551Now, I noticed the seller was local to me and has their own website, and they also sell everything through their site. Meter link on their site here:https://hollandequipmentsales.com/shop/495656319/keysight-34465a-6-1-2-digit-multimeter-truevolt-lg-2053-3/I contacted him, let him know I could drive out and asked what the best price I could get if I made it as easy and cheap on him as possible: I drive out (no shipping / no packaging), cash in hand. No chance of a screw-you-over eBay return, I test it right there and either hand over cash or don't buy. Under those conditions I was able to pick one up for $500 which was pretty great in my opinion.Anyway, I'm sure you won't be able to get that low a price with an online sale and shipping, but we discussed it (and I mentioned that I would let people on this forum know that he had these) - while he wasn't willing to pin down an 'EEVBlog users get this price', he is willing to negotiate, so I do know you can get one for less than the currently listed $695.His cell number is on their website, as is an email contact form - shoot him an email or text if you are interested.For what it may be worth, additional details I have gathered:It looks like these units were removed from service from a LG facility. As you might notice from the pictures, it looks like they were calibrated for DC volts only - I'm guessing it's the only thing they were used to measure so you can reasonably expect other ranges to not have been as recently calibrated as DC volts.When I drove out, I asked him to put a few in a warm room overnight. I brought my DMMCheck plus r8 and an old soviet-era precision 4-wire 1K resistor standard. Tested DC volts (5V), 1mA current, and a bunch of resistance. While nothing read out dead on at 5.00000 or 1.00000mA, they were quite close. These were of course not perfect test conditions, but also not the worst. I left my DMMCheck plus on before I left my home and transported it and the 1K resistor standard in a re-used medical perishable insulated shipping box to do what I could to keep it sitting at around 21 to 22C.The one I bought gave 5.00005 or 5.00004V, the other read at 4.99972VDC1mA from DMMCheck: mine read between 0.9994xx to 0.9995xx mA, the other read between 0.999393 to 0.999400100 ohm resistor from the DMMCheck: 100.033....For reference: on my most accurate bench meter at home, a HP 34401a with both the meter and the DMMCheck warmed up reads at 5.0000V for the DC volts output - I haven't recently typed down the rest of the outputs and I just got back home, so things are both powered off and even insulated, the DMMCheck has been exposed to some temperature swings in the past couple hours, so trying to get max-precision readings right now wouldn't make sense.Sorry I don't have more comprehensive data from more meters, but I was keeping him standing there and didn't want to abuse his hospitality.Anyway, the guy himself seems decent. You'll get the best deal contacting him directly and arranging to purchase from his site (since he won't get ~13% taken off the top by eBay fees), but if you want the protections afforded by shopping on eBay I'm still pretty sure you can get some taken off the price by contacting him and talking it over.Wanted to let the community know. Oh, and he also says he tries to post pictures of the items in the worst condition to prevent complaints. The one I bought is in great shape.Edit: I think I may have grabbed the only black one available, sorry guys!EDIT 2: 2025-Jan-31 T:1014- Other information I remembered that I thought to share: I had a stack of 4 to pick from when I went out (that he left in a heated room overnight per my request) and none of those units had GPIB - I'm *guessing* that is likely the case for all of them.Edit 3: 2025-Feb-3 T:2311 - Forgot about this, minor detail but more information is generally better. Most of the meters are currently set for 220 volts input, he mentioned this and I remember needing to pop out that selector bar in the back and flip it around to select 120 volts instead.Edit 4: 2025-Feb-5 T:1143 -looks like he does have one more of the black 34465a models- understandably he's pulled it out and is selling it for more, link here:https://www.ebay.com/itm/256805195293(currently shows as $859 on eBay) and link on his site here:https://hollandequipmentsales.com/shop/495656319/keysight-34465a-6-1-2-digit-multimeter-truevolt-lg-2053-4/- I'm 90+ percent sure the '17 available' on his site for the black unit is accidental, and on eBay he's only listing 1. They may be exactly the same on the inside, but they are prettier.Edit 5: (shortly after posting 4, same day) - all units I personally had eyes on had no handles. Some had rubber bumpers, some didn't, but I did not see any handles.Edit 6: looks like the black one sold. Added strikethrough on edit 4.

author: coromonadalix
author_rank: Super Contributor
timestamp: January 31, 2025, 01:03:31 pm
content: you should rectify your titlehe does not have many of the same model NOW many hp Agilent stuff BUT not many 34465and do check this one he's selling you have a warning on it, when the front rubber is removed ?and we don't see the certificate tag number to try crosschecking itdc calibration only ??

author: Kean
author_rank: Unknown
timestamp: January 31, 2025, 01:42:22 pm
content: Quote from: coromonadalix on January 31, 2025, 01:03:31 pmWhat? He has other listings but that listing still has at least 12 x Keysight 34465A available for a very good price with 30-day warranty.The listing states that not all have rubber bumpers, and they are currently set to 220V. Seems OK, and the sample in the photo does show some minor crack in the plastic front panel.Yes, they are marked as only calibrated for DC volts, and no cal sticker - but the cal of a used DMM is rarely current unless specified. If you need cal, you pay for it.

author: neverendingstudent
author_rank: Regular Contributor
timestamp: January 31, 2025, 02:54:14 pm
content: Quote from: coromonadalix on January 31, 2025, 01:03:31 pmI'm not sure what I should change about or add to the title?While the seller does have some other HP / Agilent stuff, I wasn't posting about that. While the eBay listing says 'more than 10 available' you can see on his own website (the second link) that he has 19 remaining shown in stock (as of typing this reply) - I think 10 or 19, either way counts as many."and do check this one he's selling you have a warning on it, when the front rubber is removed ?" - I'm sorry, your meaning here is a bit unclear, but I'll try to answer. I also just looked back at his eBay listing and I see he's added some more pictures, probably from a different 34465a since it has the rubber bumper and the main picture doesn't. When I went out yesterday to test a couple and pick one, he did get to see me checking the meter and going through menus - though I'm not claiming to know for sure that he added those meter menu pictures just now after seeing me look them over, can't know for sure if that's the case."you have a warning on it" - I can only assume you are talking about the label that says 'DC Voltage Only" in big red letters? If you go to his site (not the eBay listing) you can see one of the pictures taken from above of a different meter (still a 34465a) that has a sticker "VOLTAGE ONLY CALIBRATED" in red lettering. I know all of these were from an LG facility (either a closure, or they cycled out old equipment - I think from our discussion it was a facility closure though but I'm not stating that with 100% certainty) and from what I can piece together many (maybe all? not sure) where used at stations literally ONLY to test DC volts. I assume (and no, I don't know for sure, this is speculation on my part) that some bean counter figured out that if they only had their huge number of meters calibrated for DC voltage instead of full calibration, they could negotiate to pay less for that 1-function-only calibration. Just my educated guess there."when the front rubber is removed ?" - some of them have rubber bumpers, some don't. All the ones I got to personally see (he pulled out 4 of them to leave in a heated room overnight before testing) had bumpers, but I think that was just him picking out those to be nice - I don't know how many he has with and how many without rubber bumpers. You could ask him - if you contact the guy wanting to get one, I'm sure you can ask for one with bumpers if he still has some in stock."and we don't see the certificate tag number to try crosschecking it" - do you mean serial number? or something else? The one I bought does actually have a normal cal tag from Keysightfrom June of 2024(EDIT: sorry, the cal tag expired June 2024, it was done June 2023 - my apologies for being unclear, I'm editing this shortly after posting this reply), and there's a WO number on it which I'm guessing is a work order number for the calibration job - but that was the only black unit I saw and it being the newest one of the 4 he brought out was part of why I picked that one. I don't remember seeing a cal sticker like that on the others."dc calibration only ??" - as explained further up, my best guess is that many (or all) of these meters were in factory production stations with LG and were only used to check DC voltage. My best guess is that a bean counter negotiated to get tons of meters calibrated only for the DC volts function in exchange for a lower price.

author: coromonadalix
author_rank: Super Contributor
timestamp: January 31, 2025, 03:18:04 pm
content: show us the link pls and ill retract i check all his stuff and may have missed itonly this one shows up in his listing ?https://www.ebay.com/itm/186915657551?there a difference between linking a sale on ebay AND his sale store redirectionPeople do post many ebay link and don't do any follow up, I Was still being on Ebay as per 1st link, and selling like this only showing the actual EBAY 1st link is a warningothers show all meters with a number sticker and can check all pictures, if the seller made an effort to do soif you bought the black unicorn of/from his site and have paypal protection gooood happpy for you but ....And seeing you strongly react .... no need to justify the ebay game or reseller store ....the 1st link meter has a partial calibration, problems could be in it, or be outside tolerances etc ...and as i wrote you don't see the 18 other ones

author: Kean
author_rank: Unknown
timestamp: January 31, 2025, 07:07:32 pm
content: Quote from: coromonadalix on January 31, 2025, 03:18:04 pmThe one listing is for multiple units with the same basic description - you can enter a quantity greater than 1. I just tried and 19 is accepted, but 20 isn't - which matches what the OP mentions is listed on the sellers own website.This is very common way to list many items including refurbished test equipment, but I'm not a fan as I like to inspect the specific item I am buying. Some sellers also use indicative images of a similar item instead of the actual item even when they are selling just one unit. This isn't always apparent unit the item arrives and the serial number doesn't match, or different marking/damage is visible.

author: neverendingstudent
author_rank: Regular Contributor
timestamp: January 31, 2025, 09:20:34 pm
content: Quote from: coromonadalix on January 31, 2025, 03:18:04 pm"only this one shows up in his listing ?" - yes, he has a bunch for sale, but only took pictures of one (now combined pictures of 2 different ones it looks like). From when I talked with him, he does a lot of volume and his approach when he has a bunch of used 'same product X' he picks out what looks worst and takes pictures of that one.It isn't how I do it, but I never have more than a hundred listings on my eBay store, so I can afford to spend more time on each listing. Honestly, given the look of the meter he has posted,I probably wouldn't have bought one, considering it too risky that I'd get something damaged. It was only because he lives about a 40 minute drive away from me that I called and asked to come out and take a look."there a difference between linking a sale on ebay AND his sale store redirection" - um.. yes? Links to ebay are different from links to his own website. I'm pretty sure you're making a point with that statement but I don't understand. What am I missing? Or not understanding?"People do post many ebay link and don't do any follow up, I Was still being on Ebay as per 1st link, and selling like this only showing the actual EBAY 1st link is a warningothers show all meters with a number sticker and can check all pictures, if the seller made an effort to do so" - I see what you're saying there, and I agree that it isn't great, and not how I do things when I sell on eBay. I would also want individual listings with detailed pictures of each meter so I knew what I was buying."if you bought the black unicorn of/from his site and have paypal protection gooood happpy for you but ...." - I didn't buy off his site or use paypal - as I mentioned in my original post I physically drove to him so I could pick out the meter I wanted and test it while I was on-site, then pay with cash - as in literally cash, physical money."And seeing you strongly react .... no need to justify the ebay game or reseller store .... " - I'm... responding to your post in detail?"the 1st link meter has a partial calibration, problems could be in it, or be outside tolerances etc ... " - Yes. That is correct. I only tested one other meter besides the one I bought while I was there. I did also mention in my original post that it looks like they were only calibrated for DC volts. I certainly can't, and don't, make any claims about what he is selling beyond what I have already described."and as i wrote you don't see the 18 other ones" - yes, as covered above, it's not how I would publish a sales listing, but it is how he has chosen to do it..My advice, if anyone both has an interest in one of these meters but also shares your concerns about not knowing for sure what you're getting, would be to contact the guy, ask him to pick out one that looks nice and ask "hey, could you send me pictures of the one I would get if I bought from you" or something like that. No idea if he'd do it or not, but you could ask....Ok, I just wanted to share what I thought was a good deal with the community. Now all I am is frustrated, since it seems this has devolved into just arguing over the internet. I'm going to go do something productive.

author: Kean
author_rank: Unknown
timestamp: January 31, 2025, 10:24:53 pm
content: Quote from: neverendingstudent on January 31, 2025, 09:20:34 pmYour original post is appreciated, so don't worry about the negative comments. I'm slightly tempted, but fighting the urge...I'm sure coromonadalix is trying to provide helpful advice to other readers, but in my experience their comments often lack clarity. Not sure if it is their native language or just their style.

author: coromonadalix
author_rank: Super Contributor
timestamp: January 31, 2025, 11:41:16 pm
content: im not frustrated, im happy for he op as i wroteBe careful on posted Ebay links and mostly redirection on seller site, i do understand you wanted to do goodBUT as i wrote he say 19 items, use 1 item picture to describe the others, there's others not shown, that's where for me it create some problems, it is supposed to be 19 different sales with all their relevant pictures for the 19 metersthis normally raise some concerns here ... people want to see their future purchases@OP had a chance to test and see his black puppy and buy it.NOT me or the others here who may want to buy such itemThat's why i replied maybe negatively but to tell / warn others to be careful too ... that's all i had to say, this store seems to work as an auction warehouse, and i personally don't like thatIf i post an ebay link, i'll do a follow up on it's status, becauseyou did take on you to post it, you took the role of a messenger doing so,if it's sold, i'll put an sold on itPutting links and not caring for it .... meh because tons of members will click and finally see threads later it's sold or to to the mentioned link, oh it's sold damni would have not clicked for nothing if it was written SOLD you see .... some people don't like that, me 1stand sadly this phenomenon is here, and some people don't care AFTER POSTING IT .... that's a behaviour to adjust, that's all and some forums block outside / external links

author: EEVblog
author_rank: Unknown
timestamp: January 31, 2025, 11:56:54 pm
content: Quote from: Kean on January 31, 2025, 01:42:22 pmWith a meter like this, it's a safe bet that if it works, it's within spec.

author: coromonadalix
author_rank: Super Contributor
timestamp: February 01, 2025, 02:42:31 am
content: possibly yes ... here in my town with cal services a case like this is called partial calibration, and it mostly means there's possibly out of tolerances issues or problems,here they don't do : say a DC calibration and not do the others functions ? you can do a check to see if it's out of calibration, and don't do the calibration OR do the calibration, once done if it is still out, you get an out of tolerance / partial calibration, and they put a warning sticker

author: Alex Nikitin
author_rank: Super Contributor
timestamp: February 01, 2025, 12:35:05 pm
content: As a possible scenario: you have 20 of these meters, measuring DC only in an automated rig, and you need to calibrate the lot on a regular basis, how much time and money could you save doing a DC calibration only?CheersAlexP.S. - I’ve bought one of these, for that price it looks worth the risk, even though I have to pay for services of a forwarding company and the import VAT…

author: neverendingstudent
author_rank: Regular Contributor
timestamp: February 01, 2025, 08:23:33 pm
content: Quote from: Alex Nikitin on February 01, 2025, 12:35:05 pmWould you be willing to update here after the meter arrives to let us know how it looks and if everything checks out in spec (to whatever degree you can verify with what you have)? Pics?I had thought about attaching pictures of the one I bought, but decided against it since the one I bought was an outlier (being black instead of white/grey) and wouldn't represent the others the guy has.

author: Alex Nikitin
author_rank: Super Contributor
timestamp: February 01, 2025, 08:31:23 pm
content: I will be happy to do it, I have a reasonably accurate DC and AC voltage and resistance standards, and I’m familiar with this model (used it at one of my work places for over five years). The only slight problem is that I’ll receive the meter at best in about 2weeks, if everything goes well. It should be delivered to a forwarding company, processed by them (takes a few days) and later hopefully delivered to my place in the UK a week or so later.CheersAlex

author: coromonadalix
author_rank: Super Contributor
timestamp: February 02, 2025, 12:08:33 pm
content: keep us informed

author: RMSLabs
author_rank: Newbie
timestamp: February 04, 2025, 03:25:56 am
content: For what it's worth, I bought one of these meters a few weeks back. The seller was great. He followed up a few days after the sale to let me know he'd discovered the input voltage was set wrong. I've never met him, but he was great to communicate with.The meter works great and, IMHO, is a steal at this price. I can't tell if it's out of calibration (most of my work uses relative values), but it's close enough for what I need. I'd buy 2 or 3 more if I thought I'd ever use them. But I've got too many meters on the shelf already.

author: neverendingstudent
author_rank: Regular Contributor
timestamp: February 04, 2025, 04:11:02 am
content: Quote from: RMSLabs on February 04, 2025, 03:25:56 amI think he and I were talking about you at one point! Not your name, but as one of the people who bought from him. Edit: the part I recognized was him talking about the voltage selector and communicating with a customer about it.Thank you for the reminder: yes, most of the meters were set for 220, I remember popping out & flipping around the selector bar in the back when I was testing the one I bought. I'll add that to my top post.

author: neverendingstudent
author_rank: Regular Contributor
timestamp: February 05, 2025, 04:49:51 pm
content: Update 4: 2025-Feb-5 T:1143 - looks like he does have one more of the black 34465a models - understandably he's pulled it out and is selling it for more, eBay link here:https://www.ebay.com/itm/256805195293(currently shows as $859 on eBay) and link on his site here:https://hollandequipmentsales.com/shop/495656319/keysight-34465a-6-1-2-digit-multimeter-truevolt-lg-2053-4/- I'm 90+ percent sure the '17 available' on his site for the black unit is accidental, and on eBay he's only listing 1. They may be exactly the same on the inside, but they are prettier, and, well... I know I'm not immune from marketing / cosmetic choices.Adding this to the update list on the top post.

author: coromonadalix
author_rank: Super Contributor
timestamp: February 05, 2025, 05:04:39 pm
content: is the handle removed on all sales

author: neverendingstudent
author_rank: Regular Contributor
timestamp: February 05, 2025, 05:09:35 pm
content: Quote from: coromonadalix on February 05, 2025, 05:04:39 pmAll the units I personally saw had no handles. I'm thinking the LG facility they came from probably removed them - but that is an educated guess on my part only. Adding to the top post.

author: voltsandjolts
author_rank: Unknown
timestamp: February 05, 2025, 07:02:17 pm
content: Quote from: neverendingstudent on February 05, 2025, 04:49:51 pmThe tan colour modelssometimes self destruct, the dark colour models seem immune so far.

author: neverendingstudent
author_rank: Regular Contributor
timestamp: February 05, 2025, 08:09:42 pm
content: Quote from: voltsandjolts on February 05, 2025, 07:02:17 pmWell. That's disturbing and disappointing. Do we know any common failure cause among these cases? I see people discussing the front panel board, but do we know what actual component is failing? Do we know if there is a common cause?Edit: I had heard something about bad SPEAR MCU units (I think?) with the 34461a (since I recently got one of those on eBay and was researching it), but I was unaware there were also problems with the 65a.Edit: Oh, and thank you for the link with that list of various forum posts about the issue all in one, that is very helpful of you.

author: Hydron
author_rank: Super Contributor
timestamp: February 05, 2025, 08:37:50 pm
content: IIRC the MCU in them sounds like it's a hot mess, major errata and just up and die.The black colour scheme is almost as sexy as the brown-era Keithleys - OP got a great deal assuming it doesn't have the display MCU issue.

author: EEVblog
author_rank: Unknown
timestamp: February 06, 2025, 07:39:58 am
content: Quote from: voltsandjolts on February 05, 2025, 07:02:17 pmWow! I hadn't seen that.

author: neverendingstudent
author_rank: Regular Contributor
timestamp: February 06, 2025, 04:40:19 pm
content: Quote from: EEVblog on February 06, 2025, 07:39:58 amI was surprised as well. Recently (literally past week or so) I have been learning about issues with the 34461a, but for some reason I didn't think that would transfer over to the 65a (I was, at the time, operating under the presumption that the 65a had a different hardware schema for.... no logical reason in hindsight) - I learned about some of them them (61a hardware issues) because before I bought the 65a from the seller I posted about here, I bought a 61a on eBay and it had a line in the screen, and was also off by 2mV (400PPM!!) when measuring a confirmed good 5VDC source (in-calibration DMMCheck Plus r8) - this led me down a research rabbit hole on issues with the 61a, finding that the SPEAR MCU has problems, overheating problems with some chips, flash memory corruption and later hardware revisions (and for a while, a now-expired warranty extension from Keysight) to try to address it and so on. Really disappointing to learn about. I firmly expected better from Agilent/Keysight.

author: coromonadalix
author_rank: Super Contributor
timestamp: February 06, 2025, 04:53:09 pm
content: we dont hear much of the 34470a series, at least here ?the fw list the 3 models 61 65 70 ?

author: neverendingstudent
author_rank: Regular Contributor
timestamp: February 06, 2025, 07:38:57 pm
content: Quote from: coromonadalix on February 06, 2025, 04:53:09 pmThe 34470a is far less common since it costs anywhere between 3 and 6 times as much money - that's the 7 1/2 digit version of the meter.In terms of this series of meter (the 'Truevolt series') there are the 34460a, 34461a, 34465a, and the 34470a. Link here:https://www.keysight.com/us/en/catalog/key-34554/digital-multimeters-dmm.htmlThere is also the weirdly named EDU34450a which is a different form factor (they re-used a previous oscilloscope body design to save $$$ on production tooling), that meter is 5 1/2 digit, not sure how much similarity there is in design. Related (in name only?) to this meter there is the older (and this is why the prior one is weirdly / confusingly named) 34450a multimeter, which has the same form factor as the old 34401a but with an OLED screen.

author: voltsandjolts
author_rank: Unknown
timestamp: February 06, 2025, 08:25:33 pm
content: 34470A is the exact same as the '65A but with the LTZ reference and appropriate calibration. So it suffers the same issues, when in the tan colour scheme.

author: krish2487
author_rank: Frequent Contributor
timestamp: February 06, 2025, 09:10:27 pm
content: Quote from: voltsandjolts on February 06, 2025, 08:25:33 pmOkay.. to be clear... the black models do not suffer from the same problem?? I was aware of some of these issues but read elsewhere on the forum that some time in the 2018 or 2019 ( the exact date eludes me.) they changed the front panel board to address this issue ??FWIW I have a black 34460a that I got a very good deal on... and from what I can see it is a 2020 model.. and has had some maintenance performed on it by keysight.. ( something about the front panel being loose..) but so far it is holding up good... so much so.. I went and bought the lan option afterwards...

author: voltsandjolts
author_rank: Unknown
timestamp: February 06, 2025, 09:21:13 pm
content: Quote from: krish2487 on February 06, 2025, 09:10:27 pmI haven't heard of any failing.Certainly there are tan colour units purchased in 2019 that have failed, don't know the build date.Black units went on sale 2020, was it?

author: krish2487
author_rank: Frequent Contributor
timestamp: February 06, 2025, 09:29:01 pm
content: Quote from: voltsandjolts on February 06, 2025, 09:21:13 pmI have absolutely no idea.. It was an ebay buy.. but from what I can understand about the serial number..It was made in malaysia and made in 2020 or so.. MY600***** is the serial number beginning..

author: neverendingstudent
author_rank: Regular Contributor
timestamp: February 07, 2025, 12:28:32 pm
content: Regarding the impression that the newer black models aren't failing: thinking about this logically there is a limit to the degree of certainty on 'newer black models don't fail' that can be reached.From what I understand, the change in color scheme was introduced starting with 2020 production? Disclaimer - I am not absolutely certain here, maybe??? there are 2019 models? Anyone feel free to chime in if you know the year they switched for sure, my searching on the matter isn't getting solid results.Anyway, logically there have been more years of production with the older grey color scheme, there are likely a larger number of grey units in the field and secondary market, and of course statistically the older grey units will have more power-on hours and longer-aged components. That, by itself, would trend the situation towards 'more problems reported with grey units'.With that said, as I've gone down this rabbit hole, I've also read about progressive hardware iterative changes, and there is this post on EEVBlog from late 2020 describing hardware changes in a black 34465a that the owner opened up:https://www.eevblog.com/forum/testgear/keysight-34465a-in-black/So I'm uncertain to what degree of confidence I can draw any conclusions on this. Logically, absence of evidence is not evidence of absence and all. Has anyone had problems with a black series 3446X or 34470 and want to chime in? At this point I'm pretty curious, and I don't think Keysight would welcome me striking up a conversation asking 'so.... could you share your annualized reported failure rate statistics with me on the Truevolt multimeter series in contrast with every hardware revision issued? What percentage of your meters per production year had warranty claims? Warranty replacements?' Somehow I don't think I'd get a solid answer for the asking.

author: Zucca
author_rank: Unknown
timestamp: February 07, 2025, 01:37:21 pm
content: Keysight decided to go black because white is the color of innocence.

author: Kean
author_rank: Unknown
timestamp: February 07, 2025, 04:06:37 pm
content: Quote from: neverendingstudent on February 07, 2025, 12:28:32 pmThey key thing mentioned in that thread about the black 34465A is this:Quote from: razvan784 on December 31, 2020, 03:10:10 pmIt was a flaw in the LM3S micro that caused flash corruption. See attached product withdrawal notice. So any unit with a TM4C device - possibly all black units, or at least starting with ones from late 2020 - should not be affected. The main PCB in the first photo has a date code of 2028, so week 28 in 2020.

author: voltsandjolts
author_rank: Unknown
timestamp: February 07, 2025, 10:12:16 pm
content: Yes, the LM3 mcu on the main board had a known issue, but it's the ST SPEAR mcu on the front panel that causes more problems.https://www.eevblog.com/forum/testgear/keysight-34465a-reliability/msg5396783/#msg5396783I'm hopeful that Keysight addressed all these issues in the black series. I haven't opened my black unit to check and don't really want to.

author: EEVblog
author_rank: Unknown
timestamp: February 07, 2025, 10:17:35 pm
content: Quote from: Kean on February 07, 2025, 04:06:37 pmOh, oh. My 34470A has the LM3Shttps://www.flickr.com/photos/eevblog/16584500317/

author: neverendingstudent
author_rank: Regular Contributor
timestamp: February 08, 2025, 01:21:13 am
content: Quote from: EEVblog on February 07, 2025, 10:17:35 pmThat is an unpleasantly expensive instrument to discover a ticking time bomb in. I wonder how fixable this is - do we know if the LM3S can just be drop-in replaced with the TM4C? Do we have any source on a black 34470a that someone has taken pictures of the boards and chip numbers on?(Edit: I could open mine up, but I have no idea if there would be a difference between the 65a and the 70a in terms of when the chip they used changed.)Dave: if you are looking for a video idea, this might be worth making one around. Both to discuss (and bring awareness to) these issues, and to solicit detailed board and component level pictures from owners of these instruments so we can compare what year production has what components, and if the newer models with the TM4C have any other changes beyond switching away from the LM3S. I really don't like the thought of these high-end meters randomly deciding to die, and would be very interested to know if the known-bad components can be replaced with the current versions. Also if the new components are available for sourcing from Mouser or Digikey or whoever, and if the prices are reasonable.I wouldn't mind doing some hot air rework for the peace of mind that one of my nicer meters *isn't* constantly thinking of letting out the magic smoke that keeps it working.

author: wraper
author_rank: Unknown
timestamp: February 08, 2025, 01:40:51 am
content: Quote from: neverendingstudent on February 08, 2025, 01:21:13 amCertainly no, they have different pinouts. I don't know how common LM3S flash corruption actually is but I doubt that every single unit containing it will fail. My 34461A purchased in 2014 is still fine. Also you will need a newer HW firmware dump for MCU change, but if you have a FW dump for old HW, it would not be a big problem anyway as you could restore it at any moment if it gets corrupted. But I could not find anyone mentioning it, and MCU most likely is read protected.

author: EEVblog
author_rank: Unknown
timestamp: February 08, 2025, 03:52:54 am
content: Quote from: neverendingstudent on February 08, 2025, 01:21:13 amQuite the complicated issue, with many factors at play.QuoteThat would be a poor bet. You are way better off doing nothing, as it's most likely your meter will not die.People only post about these thing when something goes wrong, you never hear about 10's of thousands that continue to work fine. So what you are seeing in forum like this is a magnification effect of problems that are otherwise, statistically, minor.

author: Kean
author_rank: Unknown
timestamp: February 08, 2025, 04:44:28 am
content: Quote from: voltsandjolts on February 07, 2025, 10:12:16 pmThanks, forgot about that one.My 34465A is doing fine so far, but I won't be rushing to buy another. I bought another used 34401A instead which just arrived.

author: PlainName
author_rank: Super Contributor
timestamp: February 08, 2025, 10:02:11 am
content: QuoteJust because I am in a good mood today, I would consider swapping my nice VC8145 for your time bomb, to give you peace of mind.

author: Alex Nikitin
author_rank: Super Contributor
timestamp: February 12, 2025, 08:29:56 pm
content: The meter arrived today. When I've opened the package I was ... unamused, let's say. The packing material consisted of a bit of brown paper. there was no handle. The meter nevertheless survived a road trip from Michigan to Florida, and flights from Florida to Ohio and from Ohio to the UK. It didn't power up on the first attempt though, after I set the voltage to 240V. It was a blown mains fuse (hmm). After some cleaning and the firmware update all functions seems to be OK and even before AutoCal the meter was about +7... +8ppm up from my reference at 10V and about +14ppm at 1V, after AutoCal the difference reduced to about 5ppm at 10V and 2ppm at 1V . 10V AC was less than 0.01% up from my Fluke 510A 400Hz reference and 10K 4W was +18ppm. DC current numbers were roughly +120 +140ppm on 1mA, 10mA and 100mA (100mA on 1A range was only +10 +20ppm off). I didn't have time to check more and just left the meter running at 10V DC from Fluke 731B. Here I've found the bad news - the meter has an apparently very stable but jumpy LM399A, with regular changes of +0.7ppm (see photo). Perhaps I will try to replace the reference... . The fan is not very loud. The meter was produced in March 2016 so almost exactly 9 years old, never was adjusted (the calibration string is from 28th of March 2016) and I did find the original Calibration certificate on Keysight website (which was absolutely perfect).CheersAlexP.S. with everything included I've paid about £840 (roughly $1040 on current rates) for the meter which is a reasonable price I think.

author: neverendingstudent
author_rank: Regular Contributor
timestamp: February 13, 2025, 11:52:02 pm
content: Quote from: Alex Nikitin on February 12, 2025, 08:29:56 pm...wow. I wouldnotbe happy with that packaging job. I guess that just isn't something I was exposed to since I picked mine up in person. Not sure if it's my place to talk to him about this, maybe you should send him a private message that these are precision instruments and need better padding like a thick layer of bubble wrap.When you talk about the 'stable but jumpy' reference: I see your picture of the 10V line with some ripple and small peaks - is that the picture you are referring to? If so, how do you use that to determine there is an issue with the meter's internal voltage reference? To be clear: this isn't me challenging your statement that there is an issue with the reference; this is me not understanding how A led to B, and I'd like to learn, or have someone point out what I missed.Also, thank you kindly for the update and pointing out the packaging issue.

author: Alex Nikitin
author_rank: Super Contributor
timestamp: February 14, 2025, 12:28:10 am
content: Quote from: neverendingstudent on February 13, 2025, 11:52:02 pmThe LM399A reference in my sample is very stable as it has drifted possibly less than 10ppm in 9 years, however these 1ppm "spikes" or "jumps" is a very typical problem (almost a "feature") of these chips. Not all LM399 chips produce jumps but a large percentage do. This will limit somewhat the usefulness of the meter. It should be possible to change or even upgrade the reference (the Keysight 34470A 7.5 digit meter is essentially the same hardware except the upgraded reference) however it would require a full recalibration and if the reference is new, a long time for it to stabilize.CheersAlex

author: Alex Nikitin
author_rank: Super Contributor
timestamp: February 15, 2025, 01:32:30 am
content: I am trying the ADR1399 as the reference replacement with two modifications on the board, adding the RC network (1uF+4R7) and an additional resistor to increase the Zener current to 3mA. So far it works OK, no jumps, but the reference is new and needs probably ~500h to settle before it would make sense to adjust the meter.CheersAlex

author: voltsandjolts
author_rank: Unknown
timestamp: February 15, 2025, 02:00:19 pm
content: Upgrading the reference in 3446x series might deserve it own thread

author: Alex Nikitin
author_rank: Super Contributor
timestamp: February 15, 2025, 03:32:02 pm
content: Quote from: voltsandjolts on February 15, 2025, 02:00:19 pmIt is a bit early for a separate thread, right now I’ve worked out where additional components must go, however I didn’t have suitable resistors and the modifications look somewhat ugly. I’ve ordered bits from Mouser and when these arrive I’ll make some photos and measurements for both the old and the new references and then start a thread. The mods are very simple and the most difficult bit is to recalibrate the meter afterwards. I plan to send this meter to Keysight UK for a full adjustment after I’m happy with the stability of the reference.CheersAlex

author: Alex Nikitin
author_rank: Super Contributor
timestamp: February 20, 2025, 07:52:12 pm
content: Andhere is the reference change thread.CheersAlex

author: trilerian
author_rank: Regular Contributor
timestamp: February 27, 2025, 06:28:11 am
content: I decided to pick one up. Measurements against my DMMCheck Plus has the meter within the 1year with the exception of the capacitance, which was a bit noisy. I did use a smoothing filter but I am going to have to rtfm to figure out how to change the number in the filter.I will send mine out for a cal and adjustment, but I am happy with the purchase. Also mine came wrapped in cellophane and packed in styrofoam peanuts.Now to get a handle…