Real or fake: Keithley DMM6500 on AliExpress - Page 1
Forum section: electronics / testgear

author: neverendingstudent
author_rank: Regular Contributor
timestamp: January 26, 2025, 08:07:15 pm
content: So, I recently bought, and have had some disappointment with, an Agilent 34461a. Then a deal came around where I could buy a 34465a from an individual local to me for $500 cash, which sounds like a pretty great price, especially since I can test it first...But then I did a somewhat deep-dive into the hardware design flaws of the 3446Xa / 34470a meters (front-panel chip overheating to failure, flash corruption issues from multiple causes including just 'being stored longer than 6 months'..., extreme customer service failures from Keysight with cases being reported on this forum of Keysight simply refusing to supply support for someone who bought one of these meters 'because they are an individual, not a business'.So now I'm looking at the Keithley DMM6500 as looking pretty good to me for a modern-featured high end bench meter, and of course I'm looking to get the best deal I can on sourcing one....AliExpress has them for sale at various stores, including here:https://www.aliexpress.us/item/3256806803095426.htmlfor $1450 with free shipping, which is the cheapest price I've found so far.My first question is: is this likely to be a counterfeit unit? From my research they are indeed manufactured in China, so I can potentially see a logical reason for a cheaper price to be found there, but would the unit be real? Would it be genuine, but also a QC failed factory second?Has anyone on the forum bought one of these (or another big name-brand high end meter) from AliExpress and could chime in?As a secondary question on the $500 34465a: anyone have an opinion on that? Am I seeing a few bad cases that are standouts and not seeing the overall failure rates? Would you spend $500 on it, or 3x the price on the DMM6500?Edit: lots of people to reply to. Going to do that in one integrated reply.

author: coromonadalix
author_rank: Super Contributor
timestamp: January 26, 2025, 08:16:00 pm
content: i would ask keithley if an unit bought on ali would keep its warranty, if it's an genuine reseller / store etc ... they do write : RIGOL_Keysight_Instrument Store but is it accepted by Keitley ?for me i would check this ... over a price who could let you down later if the item has a problemordering from Ali you'll have custom fee's added too ... shipping can or could be expensive to say the least, your avatar is in USA ...

author: Brad O
author_rank: Regular Contributor
timestamp: January 26, 2025, 10:28:01 pm
content: I think it's unlikely to be counterfeit, or something like a failed build from the factory. I think most likely is that it's an older unit that has been sitting around with a Chinese distributor.Aliexpress isn't an authorized distributor, so the warranty would extend from the original shipment date, not the date the unit shipped to you. But you're comparing to a used meter so that might not matter to you.I would say $500 is a good price for any 6-1/2 digit meter. The 34465A functions almost identically to the 34461A though, so if you didn't like that one you'll likely find problems with the -65A too.

author: KungFuJosh
author_rank: Super Contributor
timestamp: January 26, 2025, 10:31:07 pm
content: Anything over I think $700 will get you a customs fee, and you won't actually save any money. Wherever you buy it from, make sure it's somewhere that doesn't invalidate the warranty. Keithley's support is excellent IME.I'd personally also buy that 65A tho. 😉

author: wraper
author_rank: Unknown
timestamp: January 26, 2025, 10:32:17 pm
content: Quote from: neverendingstudent on January 26, 2025, 08:07:15 pmCurrently sold meters have different front panel HW. No support for individuals is a UK only thing AFAIK.

author: Hydron
author_rank: Super Contributor
timestamp: January 27, 2025, 12:41:16 am
content: I really like my DMM6500 but that's nowhere near enough discount to risk going the aliexpress route - you're probably hosed if anything goes wrong with it.At that price and with the KS option on the table for $500 I'd do some research into which serial numbers have the front panel thing fixed and check out the '65A.

author: J-R
author_rank: Super Contributor
timestamp: January 27, 2025, 01:02:37 am
content: For the 34461A to be that far off, I'd imagine it's broken. I think the seller had to know that because the market price for those in fully working condition with original accessories is closer to $1,000 and up. The listing was also somewhat deceptive since it's staged a bit to look like it's fresh out of the box, but obviously from the amount of dirt on it and inside the fan it was very well used. Too bad you didn't return it within the 30 day return window. But maybe you could fix it with help from the repair forum?The 34465A is a tiny bit better than the 34461A in various respects, but if you're going to go digit hunting I'd suggest an older 7.5 digit DMM with a fresh calibration.Most US authorized sellers just stick with the list price, but that is probably because they expect you to call in and haggle a bit and they also want room for discounts. However, this price of $1,589.50 with free shipping seems pretty good:https://www.tequipment.net/Keithley/DMM6500/Top-Selling-Multimeters/?v=0From what I've seen over the years, Welectron typically has the best pricing on bench DMMs from Keithley and Keysight, even with shipping to the US. They are sold out currently, but you could ask them when they expect more in stock:https://www.welectron.com/Keithley-DMM6500-Benchtop-MultimeterWith regard to the Keysight customer service topic, there is really no issue for individuals here in the US. You can literally put anything for your company name and there is no verification required. Obviously to avoid having to provide free warranty repairs to a noob that keeps frying equipment, they ask if you're a professional at various times. If you're not able to answer the question truthfully, then maybe one of Siglent's DMMs might be a better choice. $1,000 gets you a 6.5 digit DMM with a scanner card and the UI is similar to the Keysight:https://siglentna.com/digital-multimeters/sdm3065x-6-%C2%BD-digits-dual-display-digital-multimeters/

author: bdunham7
author_rank: Super Contributor
timestamp: January 27, 2025, 01:02:58 am
content: You'd be bonkers to buy that from Aliexpress when TEquipment has it on sale for $1589 less 6% for EEVBlog members (if that applies). That's a factory three-year warranty NIB vs most likely no warranty and unknown history.https://www.tequipment.net/Keithley/DMM6500/Top-Selling-Multimeters/What did you end up doing with the 34461A? I'd be reluctant to buy a used meter that I couldn't service if needed. The old 34401A has schematics and a community of knowledge about how to maintain it. The newer ones you will struggle with if you have an issue. Why would someone sell a perfectly good 34465A for $500?

author: wraper
author_rank: Unknown
timestamp: January 27, 2025, 01:16:06 am
content: QuoteIf you can get it for $500, you can buy 3 of 34465a for the one DMM6500. If one fails, buy another one. 34461A I bought in 2014 is fine so far. LM3S1D21 MCU that has FLASH corruption issue was discontinued once TI figured out what a junk they inherited from Luminary Micro. Last time to order was in mid 2015.https://www.mouser.com/PCN/Texas_Instruments_20140630000.pdfSo I assume meters made in last 8-10 years should have no issue with that.QuoteDunno what's the disappointment but did you update the firmware? Early firmware had some flaws (like slow continuity) and lacked capacitance function which was added later.

author: J-R
author_rank: Super Contributor
timestamp: January 27, 2025, 01:36:19 am
content: The disappointment:https://www.eevblog.com/forum/chat/what-did-you-buy-today-post-your-latest-purchase!/msg5791037/#msg5791037https://www.eevblog.com/forum/chat/your-pet-peeve-technical-or-otherwise/msg5791055/#msg5791055eBay listing (corrected):https://www.ebay.com/itm/296931717960

author: neverendingstudent
author_rank: Regular Contributor
timestamp: January 27, 2025, 05:06:35 am
content: coromonadalix: good call on bringing up the warranty. I'm used to buying used and didn't think of that at first.KungFuJosh: thanks for bringing up the customs fee, on stuff I've ordered before (for less money) it hasn't come up.wraper: the 34465a I'm looking it is a used unit, don't know how old though it is 'Keysight' branded on the front instead of 'Agilent' branded.Hydron: good call on the discount not being worth the added risk. Also on researching serial numbers / what year the hardware issues were addressed.J-R: the 34461a I have is functional (for now?) but does have a line near the top of the screen and I'm worried this may be a pre-failure symptom of the known front-panel controller chip overheating problem. I'm thinking about taking it apart and looking at it with my thermal camera to see how hot it's getting (if it is a HW version with that problem) and maybe it's something I can stick a heatsink on - but then I'm not sure if that will affect the working characteristics of the meter since I would be putting a chunk of aluminum on the inside. As to looking for a 7.5 digit, there is always the 3457a plugged in by GPIB, but I'm not digit hunting so much as wanting to add a modern-feature DMM to my bench - graphical display with the ability to show trends / voltage change over time.. while still being *maybe somewhat* snobbish about the brand and model in terms of not going with a 4.5 or 5.5 digit Rigol/Siglent/Hantek model. I was looking at Tequipment as well for the reliable option, but had not thought of Welectron - thank you for suggesting them (though their site seems down at the moment), I'll check back with them later. Thank you for mentioning the Keysight service not being a US problem.bdunham7: after consideration, agreed. The less-than $150 off isn't worth it when I could get it from Tequipment. I didn't know about the EEVBlog 6% discount, thank you! I still have the 34461a - it's sitting on my bench right now actually. It has a line along the top of the screen that I worry about since I know of the front-panel controller overheating issue, and I nearly bricked it trying to (and eventually succeeding in) updating the firmware, but for now at least it does work. As for the $500 34465a: the seller is local to me and got it as part of a bunch of factory-closure auction stuff - they aren't an electronics person, just a reseller, and can't test it, though I will get to test it on-site before buying if I still want to do that (I'd bring my DMMCheck Plus for that), so I'm not worried about buying something DOA.wraper: the flash corruption / LM3S1D21 MCU may well be in there - the manufacture date on the 34461a I have is 2013 if the old HP serial number schema still holds (SN starts with MY53 - 53 years after 1960) which does make sense the cal date on the factory original cal cert of 2014. I'll have to open it up to know for sure if it has that MCU. As to my disappointment with it - that is largely my worries about the model being a lemon (at least, the earlier year models that have the known-issue hardware with the MCU and front-panel controller overheat problem) - that and it has a line through the top of the display - though I'm thinking about disassembling it to see if there is a ribbon cable to be disconnected / cleaned / reconnected or some such to address the line across the screen. I have updated the firmware - almost bricked it doing so since I missed the bit about 'YOU MUST UPDATE TO 2.17 FIRST', and then Keysight's website didn't let me download 2.17 which led to a moderately severe anxiety session, but eventually I got the firmware, downgraded to 2.17, then upgraded to 3.03.J-R: those prior posts were all in good humor, I was mostly happy with it at the time - and I also posted them before I began to have REAL concerns after researching the known issues with the meter. The eBay listing you found isn't my meter - the listing I purchased from is this one:https://www.ebay.com/itm/296931717960.

author: mwb1100
author_rank: Frequent Contributor
timestamp: January 27, 2025, 05:20:27 am
content: Quote from: J-R on January 27, 2025, 01:02:37 amThe other thing that is nice about Welectron when buying from the US is that no tax gets charged - no VAT (so you'll get a lower price than what is on their standard catalog pages) and no sales tax, which could be considerable depending on where you live in the USA. They also have an EEVBlog discount code, though I'm not sure if it's still active. And even when active it applies to most things, but not everything. Email them about it if you end up wanting to buy from them.The possible downside is that buying from Welectron might complicate any warranty issues you bring up - I don't know for sure if that's the case, but it's certainly possible. For example, you may have to ship the unit back to Germany for warranty service, or the manufacturer might just say "no warranty support" for some bogus reason.

author: bdunham7
author_rank: Super Contributor
timestamp: January 27, 2025, 05:22:14 am
content: Quote from: neverendingstudent on January 27, 2025, 05:06:35 amYou weren't concerned about the 2mV (400ppm) error?

author: J-R
author_rank: Super Contributor
timestamp: January 27, 2025, 05:37:23 am
content: I've corrected my link. That seller has sold half a dozen in the last month or so, and the listing I originally posted appears to have come from the same place: "Clarion Corporation of America".The 34465A would be a good deal if it checks out with the DMMCheck Plus. Is it white or black?The 34461A is a tough return since the issue with the display was noticeable in the listing photo. But by the time you've purchased the 34461A and 34465A, you're at $1k, which isn't far off from a new unit. Depends on whether you want some projects to work on for a while or just a ready-to-go unit that doesn't need anything.

author: neverendingstudent
author_rank: Regular Contributor
timestamp: January 27, 2025, 05:40:05 am
content: Quote from: bdunham7 on January 27, 2025, 05:22:14 amWith 11 years since factory cal, and no documentation or sticker showing cal since 11 years ago... while I genuinely would have liked to see a more accurate reading, I didn't actually think it was completely unreasonable after 11 years + who knows how long unused / unpowered storage time.While I was being humorous in my complaint - now you have me wondering, is a 2mV drift after 11 years outside of reasonable expectations?I do know my much older HP 34401a with a totally unknown last-cal date is absolutely dead-on accurate against my in-cal DMMCheck voltage reference.

author: neverendingstudent
author_rank: Regular Contributor
timestamp: January 27, 2025, 05:44:41 am
content: Quote from: J-R on January 27, 2025, 05:37:23 amAgreed, they do seem to have come from the same original source.The 34465a is unfortunately white, not the new sexy black.I'm not really worried about returning the 34401a - and agreed one of the listing pics did show the line, I just missed it. I'm... accepting of it as a project meter, for the price I think it's still OK-ish, and it did come with a factory original GPIB to USB adapter, which is good value on its own.In terms of the combined cost of the 34461a and 34465a already going over $1k... well, there is the whole Test Equipment Acquisition Syndrome...

author: bdunham7
author_rank: Super Contributor
timestamp: January 27, 2025, 05:49:26 am
content: Quote from: neverendingstudent on January 27, 2025, 05:40:05 amYes, that's whacked IMO. Certainly not in line with what happens with every other non-crap 6.5-digit meter out there.

author: wraper
author_rank: Unknown
timestamp: January 27, 2025, 03:33:18 pm
content: Quote from: neverendingstudent on January 27, 2025, 05:06:35 am99.9% chance it's a faulty display.EDIT: Not the same LCD model but most likely should work just fine as it uses pretty standard LCD, worth a try for just $9.https://www.aliexpress.com/item/1005005199455421.htmlOriginal CMT430B19N00:https://tmeho.nl/product/keysight-agilent-lcd-display-spare-part-34460a-34461a-34465a-34470a/EDIT2: Original is actually TN, so that would be an upgrade. TN is even cheaper.https://www.aliexpress.us/item/3256807487016111.html

author: neverendingstudent
author_rank: Regular Contributor
timestamp: January 27, 2025, 08:47:11 pm
content: Quote from: wraper on January 27, 2025, 03:33:18 pmThank you! And yes, for the price that is a very inexpensive part to try throwing money at the meter. Basically throwing pocket change at it for those prices, VERY much appreciated.

author: Hydron
author_rank: Super Contributor
timestamp: January 28, 2025, 09:41:24 am
content: Definitely go for IPS if you can, DMM6500 uses a COTS display with early units being TN, later IPS, the later ones look much nicer.

author: neverendingstudent
author_rank: Regular Contributor
timestamp: January 31, 2025, 01:34:02 am
content: Ok, so I went to the guy selling the 34465a at $500 (in-person cash price) and I couldn't help myself. One of them was a 2020 black model, tested good against my reference standards, and I bought it. SEXYYYYYYYYYYYYY!I'll still take care to look over the 34461a as a project meter, replace the screen and confirm which chip it has inside, but that black 34465a is being added to the bench.Oh, I posted that seller's info here:https://www.eevblog.com/forum/buysellwanted/fs-many-keysight-34465a-multimeters/- he has an eBay store and his own website, if you want one (sorry, I'm pretty sure I got the only black one) you can text or email him to negotiate price. He has the public price posted as $695.Sigh... and I *still* want to get a DMM6500... truly I have the TEA sickness...

author: Kleinstein
author_rank: Super Contributor
timestamp: January 31, 2025, 01:16:40 pm
content: The price difference for the Alibaba offer is rather small. I would say not worth the hassel with shipping, possible transport delays and complications in the warranty. It could be different for a different country with no local offers and shipping/trade complications.

author: mawyatt
author_rank: Super Contributor
timestamp: January 31, 2025, 02:14:46 pm
content: Quote from: neverendingstudent on January 31, 2025, 01:34:02 amThat's a great deal if the KS34465A is in good working order, yes the black ones do look niceYou will also like the DMM6500 with the graphing capability and the low 1Ω resistance range, the UI is different than the KS and takes awhile to get comfortable with, but very powerful and versatile DMM.Good findBest

author: KungFuJosh
author_rank: Super Contributor
timestamp: January 31, 2025, 03:51:49 pm
content: Quote from: mawyatt on January 31, 2025, 02:14:46 pmI found the UI generally intuitive on the DAQ version. The main thing I think people should know about that isn't obvious, is setting the autoexec to autoload your preferred settings on startup.

author: wraper
author_rank: Unknown
timestamp: February 06, 2025, 08:36:57 pm
content: Quote from: wraper on January 27, 2025, 03:33:18 pmI can confirm that IPS LCD from Aliexpress works fine in 34461A. Since it costs peanuts, I thought it wasn't a bad idea to upgrade TN display in my early 34461A. Good brightness, viewing angles, contrast.

author: Zucca
author_rank: Unknown
timestamp: February 07, 2025, 03:55:30 pm
content: Quote from: Hydron on January 28, 2025, 09:41:24 amHow do I tell if my DMM7510Quotehas TN or IPS?ah:https://newhavendisplay.com/blog/tn-vs-ips-whats-the-difference-/https://www.lcd-module.com/lcd-tft-code-example-programming/better-ips-tft-tn-lcd.html

author: Zucca
author_rank: Unknown
timestamp: February 07, 2025, 04:13:31 pm
content: Quote from: wraper on February 06, 2025, 08:36:57 pmyou should report it in a new thread "TN display upgrade to IPS in TE"

author: neverendingstudent
author_rank: Regular Contributor
timestamp: February 10, 2025, 02:57:18 pm
content: Quote from: wraper on February 06, 2025, 08:36:57 pmThank you for this confirmation that this specific part is compatible. I've bought 2 of them so I can swap 1 and have a spare. We'll see how it goes.

author: hugos31
author_rank: Regular Contributor
timestamp: March 17, 2025, 02:22:01 am
content: I have problems... I updated the firmware. The battery is fine... what could it be?