EEVblog

Inside the new Keithley DMM7510 7.5 Digit Bench Multimeter
What gives this unit it's superb 16ppm/1year accuracy specification?
What construction techniques have they used?
How and why are Fluke so heavily involved?
What considerations are given to the power supply and isolation aspects?
How does it compare with the cheaper Keysight 34770A meter?
UPDATE: The ADC used is a custom 32bit one for slow reading, and an 18bit AD7982 for faster readings. This chip is not marked, and there appears to be two of them on board.
Forum: www.eevblog.com/forum/blog/eev...
The Precision Thin Film Resistor Network video: • EEVblog #730 - Thin Fi...
Hi-Res teardown photos: www.eevblog.com/2015/04/09/eev...
Datasheets:
AD7982 18bit ADC: www.analog.com/media/en/techni...
LTC1050: www.linear.com/product/LTC1050
ISL28110: www.intersil.com/en/products/a...
LSK389 Ultra low noise matched JFET www.linearsystems.com/assets/m...
SSM2212 Dual matched transistor: www.analog.com/media/en/techni...
DG411 Precision analog switch: www.vishay.com/docs/70050/dg41...
TPS65251 Triple Switcher: www.ti.com/product/tps65251
Freescale MPC5125 Processor: www.freescale.com/webapp/sps/s...
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[@davesherman74]

Nicely done. Former Keithley engineer, 1997-2014, just before the model 7510 was released. I can say that the Actel FPGA at 20:00 is indeed the integrating A/D. I was the lead firmware engineer for the 6517B electrometer and that A/D was developed for both. You are correct, it's a custom design, and it's a variation of a dual-slope A/D converter. I had to chuckle at the "evil Danaher" comment, part of the reason I left. It just wasn't the same company I started with. I was among the last few new hires who got to meet Mr. Joseph F. Keithley, the founder.

[@RiyadhElalami]

Oh my oh my. Any stories worth sharing?

[@lord_haven1114]

@@RiyadhElalami apparently not LOL

[@scottydawg1234567]

I'm not an engineer (art student, actually), so I don't always understand the jargon, but that doesn't mean I'm not fascinated by electronics (rspecially old computers and such)! I love this whole channel.

[@Landrew0]

I don't understand the anti-China bias. They can build up to any quality standard (as evidenced in this video) but they can also build down to any price, but it's unfair to judge them only on that.

[@dani777dani]

"ieeeeeahhhh ieeeeaaahhhh" Dave

[@FooBar89]

that wasn't "China" building it, Tek is not a Chinese company, Made in USA, Assembled in China

[@gregd6022]

Usually jealousy in the Anglo world.. the denial is hilarious at times.. and it's only ppl who've never been to east asia.. going back to the US now feels like going through a time warp... backwards.

[@billa8671]

No. It's because the US has given their sh*t holes to china, and as such we are getting thoroughly fucked.

[@davidcasper312]

try slave labor and elite hand picked by commies, then re-affirm that...

[@jackwyz22]

Thank you for the teardown! You spend a lots of time on each video and i enjoyed it! Keep the good work up!

[@ravener96]

i love the high FPS. it's amazing. thank you for providing it, even if it increases the time you need to spend on each vid.

[@mikeselectricstuff]

Mains sensing will be so they can sync the sampling to mains freq to eliminate hum - On the Agilent you select sample time in terms of powerline cycles

[@robertcalkjr.8325]

mikeselectricstuff Umm, cough, cough; you mean Keysight?

[@andysworkshopuk]

Robert Calk Jr. Nah, he meant HP

[@andrewwhite1793]

mikeselectricstuff Both Keystrokes and Keithly have NPLC settings for changing the time this filter integrates over

[@djm384]

Thank you very much for this review, it is really well explained and described. It helped me to choose between this one and the Agilent 34470A My choice is KEITHLEY 7510

[@niuxx]

Hi Dave, do you think you could do a video on guard traces? If you haven't done already. Mainly interested in how they work, and how to design them.

[@GoldSrc_]

The thing about the same length legs on the resistors is obviously to prevent fights between the electrons about who got the longer leg xD.

[@stephenborst3535]

I want one ! Awesome stuff Dave , keep it up!

[@darrenwatson8855]

Just come to say Hi I love your videos your enthusiasm has me hooked on electronics

[@dwDragon88]

Imagine the extra cost in labor alone to hand assembly all of those odd custom assemblages, like the crazy custom AC power supply and the "LEADS WILL BE EQUAL LENGTHS" resistors. This thing is old school in all the right ways. I hope the performance lives up to the high expectations!

[@aicisha]

...and surprisingly it's made in china

[@eumoria]

having to replace optoisolators on cnc hardware it would be amazing to have them on a module like that rather than having to pull the chip off and replace on the main expensive board. every kit should have the isolation modular like that i love it

[@PacketCyclotron]

I can't stop drooling. Dave gets all the toys.

[@mjlorton]

Very nice Teardown. A very nice piece of kit.

[@FooBar89]

like the best right? :P

[@richfiles]

Oh mai!!! That's a sexy beast! :O The homespun isolation transformer was exquisite!

[@Narwaro]

They have to be careful that they dont turn this thing into a mini oscilloscope with all those logging functions and the update rate ...

[@TheMrKeksLp]

For around 4 grand you might aswell just buy a scope

[@redmist4963]

@@TheMrKeksLp with 7/5 digit multimeter integrated inside it?

[@ronniepirtlejr2606]

Maybe in 20 years from now, if the thing is still going or if they ARE even fixable, I can afford one!

[@kefler187]

Maybe by the time I retire in 32 years ? XD

[@xjet]

That's why I love my Sony HDR-PJ760VE -- it has 96GB of internal memory *AND* will take another 64GB via SD card. Beauty!

[@MotoG-ub3lw]

I'm waiting for a Keithley DMM6500 teardown video on EEVBlog

[@salahzayouna]

@ minute 15, that wire is not sense wire, the two wires are one from front and the the rear side inputs (GNDs). There should be another two connection, switched, must be coming through the board routing, to the Shunt coming from the front and rear. The two sense wires should be very thin and routed deferentially to the appropriate circuit , they are tracks not wires.

[@davidcasper312]

Thanks Dave, primo info

[@mikeselectricstuff]

I think a lot of those slots, especially round the SSM, are for rmechanical and thermal isolation

[@FooBar89]

1:00:00 except for the fan, the construction is really great, the 3458A has way more "messy" cables, and it is the top performing DMM

[@zx8401ztv]

An amazing bit of kit, i was salivating all the way through lol :D

[@douro20]

Keithley has been using Enea OSE for a long time. it is highly optimized for Power Architecture, hence their use of Freescale MPC series processors.

[@KeenanTims]

Look at the manufacture date on that LTFLU. 2012. Has it been burning in for 3 years? Probably. Crazy.

[@EEVblog]

Keenan Tims Totally missed that!

[@janoschlolmann8822]

Would be nice to see the more affordable DM6500. But it's still a very nice video !!

[@douro20]

The SSM2212 was perhaps designed by the team Analog Devices inherited when they purchased Solid State Micro Technology for Music, Inc. back in the mid-80s.

[@MsHUGSaLOT]

maybe you should do a video on those isolation traces and what they do and why they are needed. I imagine they are used to isolate induction?

[@johanlaurasia]

EEVBlog Rocks!

[@tablatronix]

The switch moves when you press it, I wonder if that is by design so it doesn't stress the joints or the board. Seems like it looking at those huge posts on it. 23:06

[@sbreheny]

Dave - could it be that the white/black wire going to the 4-terminal resistor is NOT a sense wire? If I look closely, I don't see any trace going from the sense terminal of the resistor to that wire. I suspect that it may be two different current paths through the resistor and the sense leads may be internal to the PCB.

[@tbbw]

Dave about the highres photos in my opinion your current camera and way to do it is more then enuff, i can clearly see some of the traces and pritty much all the numbers on the chips so i dont see why you would need anything more.

[@reed136]

I would like to see a larger video on the ceramic resisters, but over all great video dave!

[@EEVblog]

Jordan Reed Follow the link! I did a separate video on this.

[@reed136]

EEVblog oh ok thank you i must have over looked it. :)

[@NuclearAmouri]

"That's a critical low current trace there" *bangs on it with a screwdriver* 25:00 Why? Because.

[@MarkMcDaniel]

It looks like that Fluke-commissioned component sits on a knockout board, given the cuts and four linkage points. I wonder why it appears to be removable.

[@mvorisek5904]

Does anyone know how is the input protected? Is the accuraccy stable after some ESD events? I see two gas arrestors in the design, are they directly on the input?

[@tonyshi3688]

At 15:24 it looks like the sense trace could be isolated on the PCB layout and guarded with that exposed region, and got bridged in assembly.

[@jeanious2009]

The caps on the 17:38 mark look to be Panasonic....I have to say they did use the some nice caps not the SAM YOUNG or CHUNG CON caps you see everywhere now a days.

[@FooBar89]

42:41 the sample rate of the main ADC is actually much smaller, they use a separate ADC from Analog Devices for the 1MSPS

[@Robert-un3cf]

Yep, that MSOP part below the FPGA (U136) is an Analog Devices PulSAR ADC. 18 bit 1MSPS.

[@michaelhawthorne8696]

Great video Dave. Just saw the end of the video and was wondering if you couldn't try some recovery software to get your footage back, the data probably was laid down but you said it was a filing system problem, Recuva from Piriform may just help. When they test this device and prove its spec, what spec is the test equipment they use? How many digits can you go to before the cable connections and lengths become too problematic?

[@EEVblog]

Michael Hawthorne No, I have tried every recovery software available including Recuva, multiple times, none of them work at all.

[@KrystianBaranowski]

Any updates in 2021? Is it still the ultimate DMM for ultra low currents? I am looking for something measuring uAmps in 100mA range like the 7510, but maybe it can be done cheaper now?

[@meindertsprang7491]

That type of transformer made up from ferrite tubes, coax and enamelled wire is very common in RF transmitters and very efficient!. In this instrument they probably use it, as you mentioned, as a synchronised DC/DC converter running at a few MHz. And don't be fooled by the 0 Ohm between the input measurement ground and the coax screen: even that screen is part of the transformer. So by exciting the primary winding formed by the inner conductor of the coax loops, you can have two isolated secondary voltages: one from the coax screen and the other from the enamelled wire winding.

[@bakagaijin7452]

Those are shields. See US9478351B2 patent

[@TomashPL58]

This 2xpci connector board, also allows for easier repair in case of optocouplers failure (and it happens ;) ). It might happen at Your lab too. Remember blowing up series pass transistor on power supply as well as fuse in electronic load? Power spikes. These are nightmare especially from building ventilation and AC. I've had few problems with these (like blowing fuses in 6 audio power amplifiers and computers every 2-3 days. Try imagine horror of changing them every second day..

[@meindertsprang7491]

The IC's on that board aren't opto-couplers but capacitive couplers, using HF pulses going through tiny hi-voltage capacitors.

[@josephworrell4823]

At the beginning of this video, Dave states that the Keysight 34470 is much cheaper than the Keithley DMM7510, is that true? Let's see. . . Cost difference, if you fully option the Keysight 34470A it is $5,369 USD. The Keithley DMM7510 has no option up charges, because it is already fully optioned at $5,420 USD. This is only a $51 USD difference! Hmmm, much cheaper??? Dave didn't take this into account. Why? The Keithley DMM7510 is competitively better in many respects than the Keysight 34470A. In my view, both 7 1/2 digit DMM's are great. With that said, based on my experience, the Keithley DMM7510 is the hands-down winner! I have both meters in my electronics laboratory, my go to meter is, the Keithley DMM7510. Great engineering achievement. Keithley/Tektronix. Dave, I do enjoy your show. :-)

[@Cristi4n_Ariel]

What is it that makes the Keithley a better choice? I was planning on getting the Keysight, and now I'm undecided.

[@BMRStudio]

And all this made in China... The factory managers did a excelent job on controlling production quality! Big thumbs up for Tektronix (Keithley) !!! And for Dave :)

[@Zamsky39]

How about Your dual xeon rendering machine? Did You make it work as desired finally? Will there be another video on it?

[@zacharysyoung]

EEVblog Why bemoan Keithley manufacturing in China? I'm only 14 minutes in, but so far you're quite impressed with the construction. Did Keithley have other options you think they could have exercised?

[@EEVblog]

Zachary Young It's just, boring.

[@robertcalkjr.8325]

Zachary Young Maybe because too many US companies use slave labor?

[@soviut]

Robert Calk Jr. I think he's moaning more about the implied issues of quality, especially given some of the lower end meters he's torn down. That said, it isn't like China lack's talented people who can build to very high quality standards, they're just known for historically being the cheap low end, like Japan in the 70's.

[@yoda8693]

soviut Yes, you always get what you pay for, "even over there". There's a ton of greatly manufactured stuff from china.

[@videosuperhighway7655]

Zachary Young sad. A 4000 dollar product you would think they could afford to pay us wages. I guess you need huge markups so you can have 3 yachts one in every port. If you used US labor then its only 2 yachts. Cant have that.

[@mrnmrn1]

EEVblog Great and detailed teardown, Dave! BTW, that fan "solution" pissed off me too, in that grade of equipment... I would even pissed off of it, if I see that on a $100 eqiupment, but pleeeease, this is a $4000 monster... Michael Hawthorne suggested you Recuva as a recovery software (I cannot reply to that message). Have you tried ZAR (Zero Assumption Recovery) also? It is free for photo recovery (if I remember correctly, it find every type of files, but you should pay for enable non-photo contents recovery). Maybe free also for videos, I don't know. It saved me nearly all pictures from two different SD cards with broken file system, which other 3 or 4 free software couldn't (but I haven't tried Recuva actually). Have you got another package for 'Mailbag Monday' from that Hungarian guy, who sent you a solar cell some months ago, which is shattered during shipping (or by you while trying to "dismantle" the wrapping from it)? He said that an other solar cell is on the way, in a better packaging. I am curious what 'better packaging' means in his terms, maybe two more rolls of Scotch tape wrapped around it? I was so LOL that I was close to spit out my lungs, while watching you trying to open that package :) .

[@wadehicks9270]

Really nice meter enjoy your videos.

[@spokehedz]

My grandmother used to work at the plant in Solon ohio, making meters in the 70's... She spoke very highly of them. Made in China? Greaaaat...

[@JamesUKE92]

Isn't the spiral cutout for thermal conduction from the surrounding PCB rather than anything to do with vibration?

[@MatthewSuffidy]

If I understand properly the really fast update is maybe successful suggestive marketing. The fast rate is going to be mostly useful for zooming in and analyzing something changing quickly, and thus useful in a recorded format. Watching a blur of numbers isn't helping anything. It may come down to choices in firmware and bottlenecks in different parts of the software/hardware.

[@dhpbear2]

I'm curious why the switching supply isn't completely covered with a metal shield!

[@larry785]

Yeah but did you have to send it back after tearing it down?

[@geeus81]

Keithley must have access to to some pretty top rate solder ovens in china. with that many slots in the board i would very worried about it warping during reflow :). especially the ones around the soic 8 though the boards look quite thick 2.2mm ish.

[@jjoster]

I like the video quality.

[@ryanmcdougall7470]

Dave are you going to do a follow up video on that intercom in the car park you were repairing?

[@EEVblog]

Ryan McDougall It's dead, Jim.

[@djaysenpai]

did you record at 60FPS? it looks really smooth

[@uncensoredtr]

EEVblog Is it possible to draw the construction of that hand made transformer? I can't really get from the tight angle in the video how that's constructed.

[@FooBar89]

is the soldering lead-free? it seems to be pretty bright for lead-free

[@Cisco8484]

Those press-fit banana jacks on the back of the unit look like they'll loosen up someday. (1:02:32)

[@Dreamagine1]

Guard traces and isolation cut-outs galore!

[@Leonelf0]

Why do the processors have dedicated JTAG headers? Is the programming feature excluded from daisy-chaining?

[@jaa93997]

Exactly. Boundary scanners specifically avoid this condition, for many reasons aka manufacturing yield impact and per unit test cost

[@sarowie]

even if not: it is faster and easier/more robust to program and debug and individual chip during development then a complete chain. As of manufacturing: When programming/flash times get significant, the chip can be ordered pre programmed.

[@jaa93997]

That is also true, for small size stuff, but when you deal with flash packages that constantly change revisions, what the process engineers love to call takt time increases and they dont like long takt times, so they go like "yeah let the bscan do the job"

[@lillydoye7418]

Maybe the errors are because you have it at an angle. Its not gravity compensating like the new Tektronix scope so that might have an impact on it.

[@KeenanTims]

SPARE DAC testpoint at 43:30? What on earth could that be about?

[@mata7648]

High res photos link in the description points to the forum.

[@Saypayaa]

"I love a good knob" - Dave Jones 2015

[@marksmith3556]

Can you do a video about battery's in parallel one set of battery is a different voltage dose the weaker battery kill the good battery or ether way around ? Also do a test in series thanks

[@ChipGuy]

Thanks for doing that one twice ...PITA. And Keithley / Keysight.... just realized that Agilent's decision is even more stupid than I first thought.

[@technics6215]

30:02 No heatsink? Why? Noise is higher than effect of temperature on this 3PPM resistor? Can someone explain?

[@petersage5157]

Did anybody else notice just about all the axial resistors are mil-spec? Not particularly expensive parts, but I'd bet they're individually tested for low drift. It all goes into the high price tag; even in China that kind of labor doesn't come cheap.

[@opelize]

Do inner PCB layers also have guard traces for important signal lines?

[@sarowie]

that does not make too much sense, as the guard is mainly for preventing leakage on the surface of the pcb.

[@HienNguyen-qo2xf]

Hello. I have a DMM7510 that occasionally reports over flow. Can you help me handle the above problem? Thanks a lot

[@Multi-CoderTTV]

The pci connector is a pcie x4 connector

[@hossammoghrabi1021]

what is the practical difference in using this one vs a good affordable meter?

[@FooBar89]

accuracy, resolution, stability

[@964tractorboy]

If you tore it down any more (and handled the boards) would you have to be wary of contamination from your skin?

[@SaNjA2659]

How on Earth are they achieving 1Ms/S with a multi-slope integrating ADC?

[@hallcrash]

Wholly Sheets, BATMAN! Quite an engineering feat!

[@hallcrash]

These are space station parts crammed in an earthly tool.

[@soviut]

Does the gunk between capacitors really serve any purpose, or is it just to impress people doing teardowns? I understand that they could vibrate a tiny amount when the unit is moved, but is it enough that people have caps snap off? Or is it a noise issue? Or perhaps a heat issue and keeping them apart regulates temperature?

[@sdgelectronics]

I've seen larger caps detach from the PCB when a unit has been dropped. It probably helps a bit.

[@soviut]

sdgelectronics I figured it was possible, but would it really prevent them from dislodging when dropped? Wouldn't it make more sense to glue them more firmly to the board to take the stress off the leads? Especially when you consider any orphan capacitors without adjacent siblings. I still think it's precaution against heat more than anything.

[@sdgelectronics]

soviut Normally they would glue them to the PCB too. It is kind of pointless how they've done it in this unit,

[@robertcalkjr.8325]

soviut I heard that they do it to keep everything in place during shipping. I would get most of it out of there if it were mine. Most of it, at least on older devices, becomes conductive and causes problems later on as it ages.

[@TheJttv]

Hot air rises so they are blowing all the cold air out ..... plus it won't have eny airflow if you don't cut a flipping hole in your bench as air does not disperse well/quickly when it hits a 90 degree surface.

[@EEVblog]

Jttv the fan is practically blocked on the bottom!

[@TheJttv]

EEVblog So can i take bets for how long it will last if you lay it flat?

[@foxyrollouts]

what about heat differentials..

[@kyoudaiken]

Hey Dave, which SD-Card brand are you using? You should switch this brand, I think it does not work out great. I recommend Sandisk only. Best ones you can get. For everyone who is interested: Recovery software won't help at all. It's the way how MP4 or MOV is internally formatted that makes it impossible to recover any data. When you're recording an Index to the data chunks in the file is created in-memory in the camcorder and the actual video and audio data is just put sequentially with a fixed interleaving. However, since the data rate of both video and audio is not quite constant, the index is needed to figure out which block is audio and which block is video, and which frame number it is, etc. However, the index must be written at the END of the file, because the chunk positions are not known while recording. When the saving of this index fails, the already written data is pretty much useless. There are no streaming markers at all, there is NO way to find out the chunk sizes, etc. That's why only the index is encrypted in encrypted video files.

[@yaghiyahbrenner8902]

Big Ups Dave very good review. Another good build from China. Why doest these companies work on lowering the fan noise in their equipment

[@EEVblog]

***** I know, the fan is bloody annoying. How does it pass a design review meeting?

[@yaghiyahbrenner8902]

EEVblog db meter in a silent room? could be a possibility, source better fans? small annoyance, if we sum the noise levels from all the lab equipment in a room the noise would be pretty high (annoying like a server room). Again not a big issue as labs are noisy environments, but late night work would be annoying. Again this is probably a preference thing. Good test is to turn on all your lab equipment and measure using a db meter and get a figure. lets just refer to it as the "fan annoyance noise level".

[@robertcalkjr.8325]

EEVblog They were probably hung-over on a Monday morning...

[@robertcalkjr.8325]

***** But the noises add up.

[@yaghiyahbrenner8902]

Robert Calk Jr. Yup and the sum of annoyance goes up with it.

[@gigabytex64]

Just to be a bit rude are these units given to you to review or do you have to purchase them for teardown and testing. Can you do custom board setups for people or is that something you prefer to stay away from that sort of thing

[@sarowie]

He gets the units for review. Of course, he also buys stuff and reviews it - but more often then not older/used gear. He also acts as an kind of reseller of used measurement equipment (buy it cheap on local auction - sell it online kind of thing). Even he does not need all the scopes in the background. If your looking for a electronics engineer and youtuber for a project: mikeslectricstuff. He is surely expensive but his projects speak for them self. Dave/EEVBlog is setup differently. Dave is mainly a youtuber. Mike is mainly an engineering office.

[@gigabytex64]

Thanks

[@shuypnini9715]

hey dave, did you know you have a wikipedia page? en.wikipedia.org/wiki/David_L._Jones

[@EEVblog]

Shuy Pnini Yeah, someone finally got one approved, no idea who. Several other have attempts have been removed in the past.

[@bgdwiepp]

The fan was probably a "Fuck it, ship it" decision.

[@bgdwiepp]

also, what the heck is that tssop 80 package on the digital board.

[@EEVblog]

bgdwiepp One week from release - "oh shit, we forgot the fan!"

[@andrewwhite1793]

I have one on evaluation and did not know it had a fan. Maybe Dave's is faulty, or mine has broken...

[@SupremeCommander0]

What is the sense in cutting the PCB? Is PCB conductive?

[@bart416]

Yes, everything is conductive to some degree. So to avoid leakage over the surface of the board due to contaminants and other reasons you cut a slot into it.

[@ReneKnuvers74rk]

A fan? In another video you showed why you don’t want a fan: to stabilize and equalize temp gradients on a board of a ppm-range instrument.

[@edcooper2396]

Looking at 40:30 it seems that all the "guard traces" are being intersected by the milling machine route paths, perhaps they're part of the milling process to precisely detect milling limits?

[@Veikra]

Impressive

[@georgegonzalez2442]

the list price for that little ltz1000 ? $468.22!!!!!

[@mvorisek5904]

I am designing similar frontend. Does anyone have schematic of the input?

[@aqib2000]

REPAIR VIDEOS PLEASE, AND THANK YOU.

[@omfgbunder2008]

How come the 3A fuse has a cover but the 10A fuse doesn't? Sounds backwards.

[@andrewwhite1793]

omfgbunder2008 I think that Dave said that the 3A fuse is used in circuit on the uber sensitive ranges.

[@keansakata1015]

Dave mentioned down to a "pico amp" resolution. The 10 amp range doesn't go anywhere that low.

[@michal.gawron]

10 µA? With this update rate, add noise and look for mean value. ;-)

[@kanlayaneepromkham8958]

How to save the file to USB?

[@FennecTECH]

if we skimp on the screws we can get better resisters!

[@WoodenFloorsRock]

What is this for? Can someone please explain lol

[@Mickice]

25:15 That is what separates the boys from the men.