Finally 7.5 Digit - My "new" Keithley DMM7510 - Page 1
Forum section: electronics / testgear

author: Martin72
author_rank: Super Contributor
timestamp: July 08, 2025, 11:34:01 pm
content: It's Tony's fault...Hi,Today, or rather yesterday, my new toy arrived, a used 7.5 digit multimeter from Keithley, the DMM7510.However, it looks in very good condition, and I'd guess that the device is from 2017, as the first (and last) calibration is dated 2017 in the info section.The display film is even still on it...I bought it on eBay from someone who had probably benefited from a company liquidation, because he had several DMM7510s on offer.I don't know yet whether I'll have to pay customs duty, but even so, it was a very good deal, if not a bargain—new, it costs around 5000 plus VAT here in Germany, so I paid significantly less.The firmware is ancient and will be updated tomorrow (thanks to Josh, my Tek account is useless).If everything is technically OK, I'm seriously considering sending it to Tek for calibration.Initial tests with the DMM+ reference show no weaknesses.More will follow, as well as pictures, impressions, questions, etc.Just an open thread to read and/or join in.To be continued..

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 09, 2025, 01:43:52 am
content: I don't need a 7.5 digit DMM. I don't need a 7.5 digit DMM. I don't need a 7.5 digit DMM. I don't need a 7.5 digit DMM. I don't need a 7.5 digit DMM. I don't need a 7.5 digit DMM. I don't need a 7.5 digit DMM. I don't need a 7.5 digit DMM. I don't need a 7.5 digit DMM. I don't need a 7.5 digit DMM. I don't need a 7.5 digit DMM. I don't need a 7.5 digit DMM. I don't need a 7.5 digit DMM. I don't need a 7.5 digit DMM. I don't need a 7.5 digit DMM. I don't need a 7.5 digit DMM. I don't need a 7.5 digit DMM. I don't need a 7.5 digit DMM.

author: Kean
author_rank: Unknown
timestamp: July 09, 2025, 02:18:00 am
content: Quote from: KungFuJosh on July 09, 2025, 01:43:52 amLOL, something I also repeat for a while at least once a week. But I do have one (Prema 6047), I just keep forgetting...

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 09, 2025, 02:34:33 am
content: Thankfully, the seller denied my offers.

author: kmoonwalker
author_rank: Frequent Contributor
timestamp: July 09, 2025, 02:52:13 am
content: Quote from: KungFuJosh on July 09, 2025, 01:43:52 am

author: kmoonwalker
author_rank: Frequent Contributor
timestamp: July 09, 2025, 02:53:06 am
content: Quote from: Martin72 on July 08, 2025, 11:34:01 pmnice catch

author: jjoonathan
author_rank: Frequent Contributor
timestamp: July 09, 2025, 02:58:04 am
content: No, you DO need a 7.5 digit DMM, and this batch/glut won't last forever. Go out there and get one!(not a cult not a cult not a cult not a cult)

author: Rubo
author_rank: Regular Contributor
timestamp: July 09, 2025, 05:46:36 am
content: Quote from: KungFuJosh on July 09, 2025, 01:43:52 amKeep telling yourself that, buddyP.S. Didn't work for me

author: Martin72
author_rank: Super Contributor
timestamp: July 09, 2025, 12:12:46 pm
content: Hi,More pictures...At first I was puzzled: only a 3A input?But no, 10A, only on the back, phew...At the back you can also see the two huge fuse holders. Let's hope I never blow them:The prices for theoriginalreplacement types are completely exaggerated, between €80 and €100... for ONE, not a set.Finally, a size and depth comparison with Siglent SDM4065A-SC and SDM3065X.Hmm... Will I open the Keithley?I think so.To be continued.

author: Kean
author_rank: Unknown
timestamp: July 09, 2025, 12:34:07 pm
content: Those fuse holders... WOW!

author: Martin72
author_rank: Super Contributor
timestamp: July 09, 2025, 12:47:40 pm
content: And these are the fuses for this:

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 09, 2025, 03:42:48 pm
content: You can also use these slightly less overpriced but still overpriced fuses:Keithley FU-99-1 3A $39Fluke 803293 11A $13

author: Hydron
author_rank: Super Contributor
timestamp: July 09, 2025, 04:30:18 pm
content: I really shouldn't ask and feed the TEA, but does the seller have more? Is it one of the Chinese sellers who seem to have a stack of them?

author: w.v.s.
author_rank: Frequent Contributor
timestamp: July 09, 2025, 04:49:03 pm
content: Congratulations, nice device!

author: Martin72
author_rank: Super Contributor
timestamp: July 09, 2025, 04:58:57 pm
content: Quote from: Hydron on July 09, 2025, 04:30:18 pmYes, it was from a supplier like that, but they don't seem to have any more at the moment.But here's one more:Another one

author: HighVoltage
author_rank: Super Contributor
timestamp: July 09, 2025, 05:51:07 pm
content: Probably no need to do a calibration, unless you have a need for the certificate.Of all my instruments, my two DMM7510 are the most stable, even after years of usage.You will probably find, that yours is very accurate, even if it is from 2017When you upgrade the firmware, do NOT press the upgrade button, instead, press the DOWNGRADE button and all will work well when you have the new FW on the USB drive.

author: Martin72
author_rank: Super Contributor
timestamp: July 09, 2025, 07:18:24 pm
content: Hi,QuoteI did it and it worked perfectly—but why do you have to do the opposite of what the menu suggests?

author: TheSteve
author_rank: Unknown
timestamp: July 09, 2025, 07:38:51 pm
content: Quote from: KungFuJosh on July 09, 2025, 01:43:52 amCorrect, you need an 8.5 digit DMM.

author: Hydron
author_rank: Super Contributor
timestamp: July 09, 2025, 08:42:04 pm
content: Quote from: TheSteve on July 09, 2025, 07:38:51 pmThis is pretty much what I told myself too - while the prices on eBay are mighty tempting for a DMM7510 (there's one for $1900), I might be able to get an advantest 8.5d for that sort of money if I'm lucky. UI not as good as the Keithley, but I do have a DMM6500 for more general jobs.

author: Martin72
author_rank: Super Contributor
timestamp: July 09, 2025, 09:07:46 pm
content: 8.5 digits is really quite a lot.Above all, I imagine that calibrating such a meter would be difficult.A 7.5 digit meter can probably still be calibrated with an 8.5 digit meter, but an 8.5 digit meter itself...Checking whether a used, older 8.5 meter is still within its tolerances is also rather difficult with the usual “private” references.That's one of the reasons why I'm considering sending my 7510 in for calibration, so that I can be sure that everything is still OK, because I can't find out with the means I have here, quite the contrary.With the DMM7510, I can calibrate/adjust my references, but not vice versa.

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 09, 2025, 09:14:36 pm
content: I think it's a good choice, as long as they include adjustment in their price. Then you have a reliable reference for all your other meters and voltage refs.

author: Martin72
author_rank: Super Contributor
timestamp: July 09, 2025, 09:23:04 pm
content: Yes, that was my thinking too, that Tek should not only calibrate but also adjust and perform a general checkup.I would be willing to pay for that.Hopefully, Tektronix isn't as jerky to private customers as Keysight has become.

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 09, 2025, 10:06:05 pm
content: My experience with this has been phenomenal, but I contacted them through my business. I hope you have a great experience with them either way.

author: Hydron
author_rank: Super Contributor
timestamp: July 09, 2025, 10:34:43 pm
content: When I had to send in my dmm6500 to swap the noisy transformer Tek were good to deal with as a private individual, albeit a bit slow (though lockdowns and Brexit wouldn't have helped with speediness). Was a warranty job so can't speak as to costs, and also was a few years ago. Got a fresh cal before they sent it back which compensated the hassleShame they don't make better scopes these days, otherwise the positive experience might have nudged me towards buying more of their kit for work (we did end up with 3x dmm6500s based off my recommendation though).

author: Martin72
author_rank: Super Contributor
timestamp: July 09, 2025, 10:53:30 pm
content: At work, we still have a few Tek devices, mainly their current probes and amplifiers.Otherwise, we have separated them as needed, Siglent/Fluke/Keysight devices for the test bench, Lecroy/R&S for development.Tektronix is increasingly being replaced here because there is nothing interesting or affordable available anymore.But I have to say, in the short time I've been playing around with the DMM7510...It's a pure pro experience.

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 09, 2025, 11:01:46 pm
content: The design and workflow are awesome. The only design flaw I'm aware of with that model is that they did the weird foam glue thing for the front panel buttons, instead of a membrane or whatever else. As long as the buttons all work, hope it stays that way.I dunno if they ever changed that or not.

author: Martin72
author_rank: Super Contributor
timestamp: July 09, 2025, 11:20:17 pm
content: LOL, I know immediately what you mean....Yes, the “feel” is a bit spongy, and I also find the key lighting rather dim.But most things can be controlled via the touchscreen anyway.

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 09, 2025, 11:41:35 pm
content: Yes, but I'm guessing yours also needs "Home + Enter" to take a screenshot. The remote web view is nice too though. I think you can right-click for screenshots. I forget.

author: Martin72
author_rank: Super Contributor
timestamp: July 10, 2025, 07:36:28 pm
content: Opened it today, was very easy.The rubber bumpers are actually made of rubber and can be easily removed. Then just loosen one screw and the housing can be removed.And then the housing was off...If there were any doubts left as to whether a meter like this had to be so expensive, they vanished in that moment.The effort that went into it is intense.The 3.5A fuse is shielded by the upper circuit board, which consists mainly of ground plane, and the fan is a 3-wire model (and not exactly quiet).The bottom is completely stuffed with circuit boards.When you remove the upper circuit board with the fan, the interesting board comes into view.If I'm seeing this correctly, the references(2 ?) are heated, at least that's what the test points near the encapsulated reference indicate.I might take some high-resolution pictures and upload them to my Drive account.Either way, it's a very nice piece of technology, and I almost don't want anything else anymore.....

author: Furna
author_rank: Frequent Contributor
timestamp: July 10, 2025, 07:59:48 pm
content: Martin,did you check the 10V with TEN399?Congrats!

author: Martin72
author_rank: Super Contributor
timestamp: July 10, 2025, 08:05:27 pm
content: Hi,Not yet, will do, maybe tomorrow...(Good point from you, as the reference was calibrated with a DMM7510)

author: egonotto
author_rank: Super Contributor
timestamp: July 10, 2025, 10:18:25 pm
content: Hallo,congratulations on your new device!You could try experimenting with thermoelectricity.How do different short-circuited cables behave?A resolution of 10 nV is sufficient to detect even small temperature differences.You could try placing a pack of ice on the contact point. It will be interesting to see what happens.Best regardsegonotto

author: LiGhTMaGiCk
author_rank: Newbie
timestamp: July 10, 2025, 10:22:25 pm
content: Keithley 7510s are beasts, especially at that price used. If it powers up clean and your initial tests look good, you’re already ahead. Firmware updates can fix bugs and add features, so definitely do that. Sending it for calibration is smart if you want peace of mind for precision work. Can’t wait to hear how it performs after some real use! Keep us posted with pics and any quirks you find.

author: Martin72
author_rank: Super Contributor
timestamp: July 10, 2025, 10:31:05 pm
content: Quote from: LiGhTMaGiCk on July 10, 2025, 10:22:25 pmIt´s looking good.QuoteDid it.QuoteThat is the main reason why I am considering a new calibration.Certainty that everything is in order and therefore certainty that I have a reference device for all my applications.QuoteYou can bet on it I´ll do this...

author: tonyalbus
author_rank: Super Contributor
timestamp: July 11, 2025, 06:49:13 am
content: First: "it's Tony's fault"Sorry mansecond: great to see you are just as lucky as i was, the first signs look good.let me know about the calibration, the cost and if it was worth it, if you decide to do it.the firmware update/downgrade was in my video, maybe you skipper trough it to fastcant wait for your real test results, keep us update if you can.Enjoy!

author: tonyalbus
author_rank: Super Contributor
timestamp: July 11, 2025, 01:52:45 pm
content: Just playing a bit with a ADR1001DMM7510DMM6500

author: Martin72
author_rank: Super Contributor
timestamp: July 11, 2025, 05:10:26 pm
content: Quote from: Martin72 on July 10, 2025, 08:05:27 pmTaken earlier, reference and DMM7510 warmed up for over an hour, room temperature 22°C, humidity 66%.The names of the images are the reference values.

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 11, 2025, 05:20:34 pm
content: Pretty darn close. I think you need climate control to get any closer.

author: Grandchuck
author_rank: Super Contributor
timestamp: July 11, 2025, 05:51:31 pm
content: Be careful Martin, volt-nuttery is lurking.

author: Martin72
author_rank: Super Contributor
timestamp: July 11, 2025, 06:08:54 pm
content: Yes, there is a risk, for example earlier when reviewing the measurement results....But then I came back down to earth.The temperature at which the reference was measured is unknown, and of course “his” DMM7510 also has tolerances, and so on.Nevertheless, you want to get as close as possible, that's obvious.I will test the other functions and then contact Tek regarding calibration.

author: akatrinii
author_rank: Contributor
timestamp: July 11, 2025, 06:19:35 pm
content: Congratulations on your new purchase. Looks very nice!As an ignorant I'm asking what is the use case of a 7 1/2 digit DMM? What are you usually measuring that needs that level of accuracy/resolution?

author: HighVoltage
author_rank: Super Contributor
timestamp: July 11, 2025, 06:29:45 pm
content: Quote from: akatrinii on July 11, 2025, 06:19:35 pmPlace a temperature probe into a glass of liquid oil and let it stabilize. Then use a laser pointer from 10 meters away and point it for a second or so to the liquid in the glass and see the temperature rise by 1 u° (one micro degree).Actually the DMM7510 works extremely well as a temperature instrument, because you can set all probe parameter into the settings. And with a good Fluke standard probe, your accuracy is amazingly stable.

author: Martin72
author_rank: Super Contributor
timestamp: July 11, 2025, 06:44:09 pm
content: Quote from: akatrinii on July 11, 2025, 06:19:35 pmReferences....There will certainly be other tasks to tackle, because once you can measure so precisely...@HighVoltage:Speaking of temperature:After the warm-up period, I pressed “Autocal,” and a warning message about the temperature appeared, which I unfortunately did not note.I was able to perform the calibration, after which a temperature difference of 0 was displayed (previously it was 2.6).The previous warning was not saved in the logs.

author: jjoonathan
author_rank: Frequent Contributor
timestamp: July 11, 2025, 07:09:36 pm
content: I like that I can park it in the 10V range and see both volts and microvolts at the same time at 20fps without ever waiting for autoranging. Frames per second are very important when sniping circuits, and visual tearing artifacts on the numbers add to the charm. Unintentional thermal effects are usually in the microvolt range so under the common circumstance that you aren't controlling temperature and materials along the measurement path there is a plausible case to be made that you are seeing "all of the digits." Plus the drift behavior is known and good -- my unit is still in the 24 hour spec5 years later. Graphs are very useful for trend spotting, documentation, and seeing through noise. The digitizer is nice when you need even more speed.Do any of these things rise to the level of "need"? No. I bought it because I wanted it and had the money. Affordability varies wildly across borders, so the value proposition will vary from "wtf" to "splurge" to "slightly silly" to "too cheap to care" depending on factors that fall squarely in the category of "life isn't fair." If you are looking at these capabilities and thinking "I could do it cheaper," you are correct! But I like my DMM7510 and I like that I don't have to spend time on those workarounds. Years after I bought it, my DMM7510 makes me happy every time I look at it and see the digits flying by at ridiculous speed, and that itself is worth something

author: Martin72
author_rank: Super Contributor
timestamp: July 11, 2025, 09:21:53 pm
content: Quote from: Grandchuck on July 11, 2025, 05:51:31 pmI just looked in the manual...It describes how to measure DC as accurately as possible. I must have forgotten to set two parameters earlier, so I'll do that tomorrow.However, I happened to get the warm-up time right; the manual says 90 minutes...90 minutes – I'll never complain about the times on my smaller meters again.And I sent a calibration request to Tektronix earlier.In my inquiry, I asked about the possibility of calibration for private customers, then about calibration with measurement data (calibration without data can also be requested), and finally asked whether my DMM7510 is in a database for initial calibration at the factory.If so, I would like to see the data.Let's see if and when Tek responds.Alternatively, I could also have the 7510 calibrated by Welectron, either ISO or DakkS.In any case, they offer this service on their website:https://www.welectron.com/Keithley-Benchtop-Multimeter-DMM7510-DAkkS-CalibrationPrice ? On request...

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 11, 2025, 09:30:16 pm
content: Quote from: Martin72 on July 11, 2025, 09:21:53 pmLike when some douchebag says "if you have to ask, you can't afford it." 🤣

author: Hydron
author_rank: Super Contributor
timestamp: July 11, 2025, 11:16:06 pm
content: When I asked Tek sent me the cal measurement data for my DMM6500 (cal just before shippment), along with another bonus set from when it was first manufactured (was ex-demo so over a year old when I received it, albeit spotless). I also got the full cal data when I got the transformer fixed, so I have 3 sets (I should really look at the numbers to check drift, just never got around to it).Hopefully the same helpful attitude is still present (~4 years ago)

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 11, 2025, 11:41:56 pm
content: You can usually download the cal certificates directly:https://www.tek.com/en/calibration-services/certificate-downloadETA: I dunno if that will work for the meter. I thought there was somewhere to get it tho. 🤔Thanks,Josh

author: EEVblog
author_rank: Unknown
timestamp: July 12, 2025, 04:18:14 am
content: Quote from: Kean on July 09, 2025, 12:34:07 pmStill no way a high energy system is coming near my 7.5 digit meter

author: tonyalbus
author_rank: Super Contributor
timestamp: July 12, 2025, 07:00:10 am
content: Quote from: Martin72 on July 11, 2025, 09:21:53 pmi Asked Welectron also, then not Marco but someone else answered the email telling in different words: they only calibrate items they sell , so it was a NOsilly thing is, the calibration, with those two options you mention, are actually items on their website..Anyone know if Marco is okey? (never had replies on my last emails)

author: tonyalbus
author_rank: Super Contributor
timestamp: July 12, 2025, 07:06:52 am
content: Quote from: KungFuJosh on July 11, 2025, 11:41:56 pmpitty : A Calibration certificate was not foundEDIT: Strange also not for my DMM6500 that was bought from Welectron last year

author: tszaboo
author_rank: Super Contributor
timestamp: July 12, 2025, 08:43:46 am
content: Quote from: Martin72 on July 09, 2025, 09:07:46 pmYou can calibrate a 3458A with just a 10K resistor (like WEkom) and a Fluke 732A.But then, you turned one problem into two.The 3458A is really nice, I had one near my workspace for a few years. You know - you can measure the voltage drop of an LED being turned on, on a solid ground plane - kind of nice.I wouldn't mind a follow-up for that, but by the looks of it there isn't a willingness in any companies to make a modern 8.5 digit meter.

author: Martin72
author_rank: Super Contributor
timestamp: July 12, 2025, 08:56:25 pm
content: Quote from: Martin72 on July 11, 2025, 09:21:53 pmNot much has changed since yesterday, which is a relief because, to put it bluntly, with these settings, you can go and have a coffee before anything happens.(Filter: 100, PLC: 10, Range: Manual)

author: tszaboo
author_rank: Super Contributor
timestamp: July 12, 2025, 09:04:27 pm
content: Quote from: Martin72 on July 12, 2025, 08:56:25 pmTry 1000 NPLC with auto zero. 40 seconds before anything on the VFD.

author: Martin72
author_rank: Super Contributor
timestamp: July 12, 2025, 09:17:06 pm
content: Quote from: tonyalbus on July 12, 2025, 07:00:10 amIn addition, Iknowthat Welectron does not calibrate the devices itself, but sends them to a specialist laboratory.However, I will only pursue this further if Tek refuses to calibrate the device or offers to do so at an excessive cost.

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 12, 2025, 09:30:19 pm
content: Quote from: Martin72 on July 12, 2025, 09:17:06 pmYou'll be fine. Have you registered your DMM in an account on their site yet?

author: Martin72
author_rank: Super Contributor
timestamp: July 12, 2025, 09:34:39 pm
content: Does that still make sense for a used device?

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 12, 2025, 09:43:23 pm
content: Quote from: Martin72 on July 12, 2025, 09:34:39 pm100%. I did, and the service I got was great.And I had to do it all through the website, with the registered device. Then I was also able to track the progress of the repair service.But I sent you some referral info, you might be able to get a 20% discount that way. So try that first.

author: temperance
author_rank: Super Contributor
timestamp: July 12, 2025, 10:22:26 pm
content: QuoteI'm a speed reader. That's why I solely use 2 digit meters with flash converters.

author: 2N3055
author_rank: Super Contributor
timestamp: July 12, 2025, 11:40:29 pm
content: Quote from: temperance on July 12, 2025, 10:22:26 pm

author: temperance
author_rank: Super Contributor
timestamp: July 13, 2025, 01:49:11 am
content: If I'm not mistaken, I see a switching power supply in there. That part on its own is interesting because that can't be a standard off the shelf power supply. Does anyone know what is in there?Or maybe someone can try to measure the common mode noise between earth and the input terminals?

author: Kleinstein
author_rank: Super Contributor
timestamp: July 13, 2025, 05:18:28 am
content: The switched mode power supply is somewhat special as it uses coaxial cables to get near perfect shielding at the transformer. There are some threads about the DCDC converter already.https://www.eevblog.com/forum/metrology/dmm7510-coax-transformer/msg4840400/#msg4840400Because the coax cable takes up quite some volume the SMPS part needs a relatively large core and is expected to get a not so good efficiency.The DMM7510 like many of the Keithley meters have some issue with low frequency noise. So it is good for short integration (like 1 or 10 PLC), but averaging over longer time or using the digital fitler is not improving things as much (e.g. way less that the 1/sqrt(N) for independent readings).https://www.eevblog.com/forum/metrology/dmm-adc-noise-comparison-testing-project/msg1366061/#msg1366061So doing the 100 to 1000 PLC conversions (40 seconds) is a range where the meter is not especially good.

author: Martin72
author_rank: Super Contributor
timestamp: July 13, 2025, 07:54:56 am
content: QuoteThis is likely why the manual recommends 10 PLC.However, the corresponding setting can only be set to 12 anyway.

author: Kleinstein
author_rank: Super Contributor
timestamp: July 13, 2025, 08:25:38 am
content: It is common for many DMMs with multi-slope ADC that the integration time in one converion is limited. Insteady of > 10 PLC conversion often averaging over multiple AZ cycles are used. This is to reduce the 1/f noise contribution as the speed of the AZ loop sets the lower frequency limit. There may be a balance between noise that gets better with averaging fast conversions and INL and switching artifacts for the input that gets better with a bit longer integration at a time.The extra LF noise in the DMM7510 is however also presenst for the average over multiply 5 or 10 PLC converions, like with the digitial filter. It is still not 100% clear what causes this noise, but it looks like some not ideal software is involved as extra trigged readings can improve on it a little.

author: temperance
author_rank: Super Contributor
timestamp: July 13, 2025, 11:47:14 am
content: Interesting transformer. Thanks Kleinstein for the link.https://youtu.be/uvgJ2zAxgAY?t=284051min22 you can see the transformer.The logic board is powered by a regular SMPS and the ADC board is powered from the regular SMPS trough this transformer with coaxial cable windings. The communication between the logic board and the ADC board seems to have been done with ISO7242 digital isolators with only 2 pF barrier capacitance, or in total 6 pF with three of those. (located on the "back plane")Can someone measure for me the capacitance between the neg. input terminal and the chassis? I wonder what the total capacitance looks like.The transformer core looks like a smaller core mounted into a larger core or is this "smaller core' a plastic spacer?Well, I'm now tempted to buy one just to investigate how this thing works...not because I need those digits. Thank you lads.

author: Hydron
author_rank: Super Contributor
timestamp: July 13, 2025, 02:38:20 pm
content: Quote from: temperance on July 13, 2025, 11:47:14 amNot gonna lie, I have the same temptation...

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 13, 2025, 03:29:48 pm
content: Goooood, let the TEAS consume you.

author: tonyalbus
author_rank: Super Contributor
timestamp: July 14, 2025, 06:16:18 am
content: Playing with a ADR1001 ref. man i love this new(old) DMM7510

author: Martin72
author_rank: Super Contributor
timestamp: July 14, 2025, 11:42:46 am
content: Quote from: Martin72 on July 12, 2025, 09:17:06 pmI got a reply from Tek...ISO calibration including return shipping: €670, with measurement report: €800.I need to think about it some more...

author: tonyalbus
author_rank: Super Contributor
timestamp: July 14, 2025, 11:46:29 am
content: Whoops... i thought about it already very quick ... its a no for me.but without ISO ?

author: Martin72
author_rank: Super Contributor
timestamp: July 14, 2025, 11:51:33 am
content: There is nothing under ISO, that is basically the standard. Above that, there is DakkS, which Tek also offered me for almost 1000....Where did you get the evaluation board? Don't say Mouser or Digikey...

author: tonyalbus
author_rank: Super Contributor
timestamp: July 14, 2025, 12:08:52 pm
content: Quote from: Martin72 on July 14, 2025, 11:51:33 amSend by a friedly viewer.

author: Martin72
author_rank: Super Contributor
timestamp: July 14, 2025, 05:48:23 pm
content: 4W measurement on an Isabellenhütte shunt, 50mOhm.For a quick and dirty job, the result is good, even if it is outside the tolerance range (0.5%), but then again, the shunt is not cooled.

author: Sorama
author_rank: Frequent Contributor
timestamp: July 14, 2025, 05:51:07 pm
content: Quote from: tonyalbus on July 14, 2025, 12:08:52 pmYou fried a viewer?You should make a review of that

author: bson
author_rank: Unknown
timestamp: July 14, 2025, 06:33:42 pm
content: Quote from: akatrinii on July 11, 2025, 06:19:35 pmOne nice use case is to characterize the linearity of a 20-bit DAC or ADC to within a few percent without the fuss of range switching.

author: temperance
author_rank: Super Contributor
timestamp: July 17, 2025, 01:34:58 pm
content: QuoteAs far as I know, they use ultra low distortion sine waves to do this.https://www.analog.com/media/en/technical-documentation/technical-articles/ubm_edn_20110811%2018bit%20adcs%20ad%20free.pdf

author: Dr. Frank
author_rank: Super Contributor
timestamp: July 17, 2025, 01:45:00 pm
content: Quote from: Martin72 on July 14, 2025, 11:51:33 amMartin,I guess, you don't need an official DAKKS calibration, a volt-nuts grade adjustment of your instrument should suffice.I recently imported the Volt and the Ohm to 0.5ppm uncertainty level, and I acquired all necessary sources so I'm able to calibrate your KEI 7510 completely, for free of course.As it's from 2017, I guess only a few ranges have to be adjusted.If you're interested, just send me a PM for further details.Frank

author: Martin72
author_rank: Super Contributor
timestamp: July 17, 2025, 01:51:29 pm
content: Hi Frank,That sounds interesting for now.It would be a good opportunity to clarify in advance whether everything is really OK with the meter.I'll think about it and get back to you.Thanks!

author: Martin72
author_rank: Super Contributor
timestamp: July 17, 2025, 01:54:42 pm
content: Quote from: temperance on July 17, 2025, 01:34:58 pmThe circuit looks familiar and reminds me to finally finish my Janascard oscillator (power supply)....http://www.janascard.cz/PDF/An%20ultra%20low%20distortion%20oscillator%20with%20THD%20below%20-140%20dB.pdf

author: temperance
author_rank: Super Contributor
timestamp: July 17, 2025, 03:06:53 pm
content: A very precise method to achieve ultra low distortion is to low pass or band pass filter a square wave. The method is not adjustable but can achieve extremely low distortion figures.

author: Martin72
author_rank: Super Contributor
timestamp: August 02, 2025, 10:21:07 pm
content: I have now written to four calibration laboratories that I know of and received four rejections.The last rejection stated the reason that is probably behind all the other rejections.They simply cannot calibrate a 7.5-digit meter due to a lack of references.

author: tonyalbus
author_rank: Super Contributor
timestamp: August 02, 2025, 10:34:46 pm
content: Hi Martin,Thanks for sharing, so its 600,- from Tek or not it seemsi bought a 399ten(ADR1399 shell) from CircuitValley , he writes down the value from his calibrated 7510.mine was only 20uV off from his, at 10Volt, that would be 2 ppm , so i feel good.Maybe you can consider the offer from Dr Frank, i did some research on the LTZ1000, and there is a Dr Frank involved who is a Volt nut as nut as they get,so if he is the same Dr Frank, he will have some very good standards. (just that you know)

author: KungFuJosh
author_rank: Super Contributor
timestamp: August 02, 2025, 10:54:06 pm
content: Get a quote from Keysight. They also have the 34470A. My guess is their price will be worse, so at least you'll feel better about the Tek price.

author: Scottjd
author_rank: Frequent Contributor
timestamp: October 13, 2025, 10:14:18 am
content: Martin, congrats on your purchase.As I have been reserving and reading though about the DMM7510 I have seen people post the link to search the serial number for manufacture call certificate. And most of the time it doesn’t work for some reason. I also wasn’t able to get that to work with a serial number I tried.I am working with a seller on eBay now and managed to find this link, thought I would share it.With this I was able to pull up the shipping date of when it was sold, this may not be the actual manufacturing date but at least it tells you when it was first opened and used. It also showed if the original purchaser had and contract like an extended warrenty or calibration contract.https://www.tek.com/en/services/test-equipment-repair/warranty-status-searchNote: You may have to search more than once with different models like:DMM7510DMM7510-RACKThis is more unlikely since “NFP” is No Front PanelDMM7510-NFPDMM7510-NFP-RACK

author: Martin72
author_rank: Super Contributor
timestamp: October 13, 2025, 01:49:28 pm
content: Thanks for the reminder. I had already tried it there once, but it didn't work, as was the case for many others.Well, with your instructions regarding the input, it worked.The “secret”:The serial number...I entered it as it appears in the system information.That didn't work; you have toomit the “0”at the beginning (as on the barcode sticker on the back of the device), then it works.Nice.

author: Scottjd
author_rank: Frequent Contributor
timestamp: October 13, 2025, 02:39:22 pm
content: Im glad it worked. Were you ever able to get it calibrated?I reached out to two local places that do NIST traceable cals and waiting for a response. But I don't have the meter yet, I did pull the trigger and buy it. Now just waiting on shipping.Not even sure I will need it. Based on the pictures it had a cal sticker that only expired 4 months ago from STIEE based in Shanghai.Once its arrives I am planning on reaching out to STIEE and see if I can get the last full cal data sheet.I might to go with a DMMCheck Plus (support local 3 hours north of me), and between that and my known precisions resistors and cap standards that might satisfy that need to accuracy.

author: Martin72
author_rank: Super Contributor
timestamp: October 13, 2025, 02:52:56 pm
content: After being turned down by five calibration laboratories (“We can't do 7.5”), I now have one last option before I actually have to go to Tektronix.Namely, “our” external calibration lab, which will soon be coming to us to calibrate our scopes and meters for a week.I'll ask them if they can also calibrate 7.5 digits.They won't be able to do that directly at our site, because they always bring a Fluke calibrator with them, and I don't think it can do it.I would like to ask Tektronix for the first protocol to see what the drift is when it has been recalibrated.

author: exe
author_rank: Unknown
timestamp: October 16, 2025, 07:21:32 am
content: Aw, what you guys have done to me... After resisting for months I gave in, when to ebay and made an offer... I haven't bought it yet, going back and forth with the seller about pictures and price, but I think it's zero chances for me to get off the hook now.I blame Tony for my addiction!

author: Hydron
author_rank: Super Contributor
timestamp: October 16, 2025, 07:58:10 am
content: Only reason I've survived temptation is with other drugs - namely already having a DMM6500 and by jumping straight to the good 8.5 digit stuff with a R6581T. Still though, it's hard when they're right there at a great price.

author: exe
author_rank: Unknown
timestamp: October 16, 2025, 08:25:21 am
content: I'm upgrading from my K2000, which I love and it serves me well (and also has no fans inside it!), but DMM7510 seems to be in another league.PS made my payment, there is no way back now.

author: Kleinstein
author_rank: Super Contributor
timestamp: October 16, 2025, 08:36:40 am
content: The DMM7510 is a different league than the K2000. A big point is the LTFLU reference compared to the LM399 found in most 6.5 digit DMMs.The DMM7510 is more comparable to the Keithley 2002. The main justification for the K2002 is the 20 V range.

author: KungFuJosh
author_rank: Super Contributor
timestamp: October 16, 2025, 03:56:59 pm
content: I have to keep reminding myself that I don't even need the 6.5 digit resolution I already have. I definitely don't need 7.5 or 8.5 digits. Nope, don't need it. Stillll don't need it. Must resist!

author: MathWizard
author_rank: Super Contributor
timestamp: October 16, 2025, 06:47:30 pm
content: What's the main benefit of a 7.5D over say 6.5D meter? Is it like for more resolution on higher ranges, like if your BJT circuit has the base at 150V, and you have to use the 200V range ?Also do they increase the input impedance any amount for a typical 7.5D meter ?I want to get an old Electrometer, with really high input impedance, so I don't load down certain circuits, like trying to measure a BJT's VBE, or measuring other high-Z circuits like in a typical DMM or scope. But then if some old Electrometer only has 3-4 digits, that will be disappointing as well.

author: jjoonathan
author_rank: Frequent Contributor
timestamp: October 16, 2025, 07:41:03 pm
content: With DMM7510, you can park it in the 10V range for fast updates and see both volts and microvolts at the same time. Single digit volts are high enough for many circuits and microvolts are precise enough for anything that you didn't sweat the metals and temperatures of every junction over and they line up with the "groups of three digits" in unit names. It's a convenience sweet spot for a huge chunk of the engineering population.

author: exe
author_rank: Unknown
timestamp: October 16, 2025, 08:16:34 pm
content: To me it's more of an emotional purchase. I'm happy with my K2000, it seems stable down to the last count or two (measured against ADR1399).What I want:- better connectivity (e.g., usb)- faster update rate to measure, e.g., LDO noise (K2000 can only do 50 readings/s continuously through 19.2k serial)- plots looks fancy- digitizer to use as an "oscilloscope" (never tried that, but want to play with it)- evaluate ADC linearityI also realized I have special tools that do better job than most, even precise DMMs:- simple diy ammeter that has leakage below 10fA (though not easy to setup to measure that)- LCR tweezers to measure capacitance- milliohmmeter for shuntsSo, for me a better purchase would be a source meter, but they cost a fortune. This DMM7510 (provided it will arrive and will function properly) more like a new toy.

author: Martin72
author_rank: Super Contributor
timestamp: October 16, 2025, 08:21:26 pm
content: Quote from: MathWizard on October 16, 2025, 06:47:30 pmFor example, Siglent SDM3065X, SDM4065A, and Keithley DMM6500 offer a selectable input resistance in the DC range of 10Mohm or 10Gohm.The 10 G ohms do not come close to the impedance of an electrometer, but they are many times higher than is usual for multimeters.

author: Martin72
author_rank: Super Contributor
timestamp: October 16, 2025, 08:26:49 pm
content: Quote from: exe on October 16, 2025, 07:21:32 amSee my starting post...Did you buy it from a Chinese dealer like Tony and I did?

author: exe
author_rank: Unknown
timestamp: October 16, 2025, 08:40:33 pm
content: Quote from: Martin72 on October 16, 2025, 08:26:49 pmTbh, I just clicked a cheapest price on ebay from those that show "genuine" photo, then negotiated a little bit.Now I think I should have done a bit of research. Oh, and also I asked the seller about cosmetic condition, and I have an impression they don't really have the device. It seems they will get it somewhere and then ship to me.They promised to send photos beforehand for my approval, but I'm a bit skeptical about that. I also asked to put full price on the customs declaration, just in case things go south.PS for those who consider buying I can disclose price, this might help with negotiation. Just PM me. However, keep in mind that I haven't received my item yet, and the whole thing looks a bit fishy. But I hope for ebay buyers protection. I don't want to put price here so not to upset current buyers in case my price is lower, but, as a buyer myself, I'd like to know what is a "good price", hence I'm willing to share the data.

author: KungFuJosh
author_rank: Super Contributor
timestamp: October 16, 2025, 09:06:33 pm
content: If you didn't get it less than $1700, don't worry.

author: Scottjd
author_rank: Frequent Contributor
timestamp: October 16, 2025, 10:00:11 pm
content: Quote from: KungFuJosh on October 16, 2025, 09:06:33 pmAre you including shipping?I know the cheapest when I was looking was $1,500 USD but had a shipping fee of $250. The one I went with (when it arrives) was listed for $1,860 USD with free shipping.I went with that for some minor reasons compared to the cheapest option like:1. “30 days returns.Sellerpays for return shipping” - This was a big one for me with shipping costs from US to China.2. Includes applicable import fees—you won’t pay anything extra after checkout. Personally I have not ordered anything big since tariffs started to hit, but I am hoping that claim covers the tariff costs.3. And eBay Money Back Guarantee, only helps if you have an issue and the seller ghosts you in my experience.4. Said it comes with a one year warranty * Not holding my breath on this one.For me its was worth the extra $80 over the cheapest cost+shipping option for the return policy marked on the advertisement.Last year I bought a B&K Precision 9205B that claimed fully tested and arrived not working. Self test pass doesn’t always mean it works. That was a US seller and still would have cost me a lot on return shipping because of the weight and size. They were going to send a return shipping label no questions asked because it was stated seller pays return shipping, and 30 days returns.Luckily we negotiated and I got an about half refund for a broken unit and I took the gable that I could repair it instead.

author: Hydron
author_rank: Super Contributor
timestamp: October 16, 2025, 10:19:25 pm
content: I wonder where this stock of cheap meters is coming from - maybe an edict from the govt to replace western gear with local? Or a big company clearing out a bunch of meters that are either not needed or have hit a 5yr replacement date or something? Be nice to know if this is the new normal or whether they're going to dry up shortly (the latter would increase the temptation mind!).

author: Martin72
author_rank: Super Contributor
timestamp: October 16, 2025, 11:38:33 pm
content: At first, I was afraid that it was some kind of “gray area” that was being sold off cheaply.But after successfully tracking my meter at Tektronix, I assume that it's a kind of liquidation/new purchase of measuring equipment, whether it's a measuring laboratory or a company's testing department.I paid less than €2,000 for it. Here in Germany, you would pay more than three times that amount for a new one today, or at least 2.5 times as much.So I'm just happy to have an excellent measuring device at a good price.

author: KungFuJosh
author_rank: Super Contributor
timestamp: October 18, 2025 01:12:12 am
content: Under $1700 including, shipping, taxes, etc. is a decent deal. Around $1800ish all-in is pretty commonly available to any reasonable seller on eBay.

author: exe
author_rank: Unknown
timestamp: October 18, 2025 07:14:06 am
content: Omg, there is seems to be a competition between sellers. This came unsolicited. I didn't know that other sellers can see my transactions and freely send me offersThe price is higher than what I paid. My seller removed the listing quickly after purchase. Wars of bots?

author: Scottjd
author_rank: Frequent Contributor
timestamp: October 18, 2025 07:43:24 am
content: I don’t know if it’s bots or what. But I do know I had a few different ones in my carts before I made my decision and never received an offer. Since I made the purchase I have received 4 different offers.I wonder if eBay gives you a grace period to cancel and this is allowing others to try to poach sales 😂FYI all 4 offers were higher, and from sellers that had some of the highest prices in that bracket.Update:Make that 5 offers, I just got the same one you received. I was turning them down, but I am just ignoring them at this point.

author: Hydron
author_rank: Super Contributor
timestamp: October 18, 2025 08:51:18 am
content: I think it sometimes sends automatic offers if you've even just viewed stuff that has auto-offer configured by the seller. Can be pretty annoying tbh.

author: KungFuJosh
author_rank: Super Contributor
timestamp: October 18, 2025 02:27:47 pm
content: Hydron is correct. If you're a seller on eBay with a product people have shown interest in, you can have eBay send automatic offers. The offer discount is predetermined by the seller, and has nothing to do with the buyer other the buyer having shown interest in the same or similar product.Sellers also have their items limited to regions (most of my items are only available to US buyers), so if two people show interest in the same item, but one of them is not in the same region, they won't necessarily get the same offers.Tip: If you're interested in something, watch it before doing anything else. Often watching it is enough to receive an offer if the seller has offers enabled (this is still true for listings without Best Offer options).Thanks,Josh

author: Hydron
author_rank: Super Contributor
timestamp: October 18, 2025 03:23:25 pm
content: I don't sell on eBay but this matches my experience. I wish it was only for "watched" items rather than also ones you've viewed - only a small proportion of stuff I've viewed is actually of serious interest so it ends up just being really spammy.RE the regions thing, this is a total mess if you have potential shipping addresses in different countries, I keep needing to change default shipping address just to buy or offer on stuff (and also switch between ebay.co.uk and ebay.com), and you don't always even see stuff that you could actually buy. I read somewhere (no idea on accuracy) that they are stuck on an ancient codebase that stops them fixing this sort of shit?

author: KungFuJosh
author_rank: Super Contributor
timestamp: October 18, 2025 03:53:10 pm
content: I dunno, the codebase doesn't make sense. Things can usually be updated, and I'm guessing the regional functionality is as they want it to be.Those restrictions are supposed to limit access, and what you're describing are ways to get around those restrictions.My items that are listed for sale in US only aren't viewable outside of the US, or at least not without a US shipping address. I'm not sure how they do that part on eBay. On AliE, you only need to change your shipping country on the topbar and it will show things otherwise restricted.I do wish that people could still view the items on eBay even though they can't buy them in their region...but that's allegedly only to make it easier to sell stuff off of eBay.

author: Hydron
author_rank: Super Contributor
timestamp: October 18, 2025 03:57:26 pm
content: They should just let you pick shipping address in these situations instead of showing an error and forcing you to constantly fiddle with your default addresses. Anyway OT rant over.More on topic, has anyone from the UK gotten one of these, and what was the experience with VAT etc if so? Are the sellers declaring full value etc?

author: Martin72
author_rank: Super Contributor
timestamp: October 18, 2025 04:59:10 pm
content: Looking at the reviews, “my” dealer had sold 5 DMM7510s (currently, they have nothing on offer).I bought mine on July 2 and received it on July 8.I paid the amount converted into euros via PayPal and had no additional costs.

author: Scottjd
author_rank: Frequent Contributor
timestamp: October 18, 2025 06:32:21 pm
content: Quote from: Martin72 onYesterdayat 04:59:10 pmI wish. You received yours about as fast as it took me to get a shipping label printed.Mine was bought/paid for on October 12, just got the tracking and shipping label printed this morning.