EEVblog 1540 - The $80 Zotek ZT-702S Osciloscope Multimeter REVIEW
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- Опубликовано: 10 июл 2024
- Is an $80 combo oscilloscope/multimeter any good? A look at the Zotech ZT-702S, with street price around US$60
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00:00 - Zotek ZT702S Oscilloscope Multimeter unboxing
01:51 - Just STOP IT, ok! LOL
04:16- Teardown
08:31 - Oscilloscope front end and processor
11:43 - First turn on
14:53 - WTF! FAIL!
15:27 - The bargraph is hopeless
17:45 - The oscilloscope function
21:17 - USB drive mode and screen capture
23:01 - I can't screw the BNC in!
24:45 - Oscilloscope Overload issue
25:48 - Multimeter overload testing
26:34 - The battery life really sucks
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Nice review! Thank you Dave!
Actually, this was the first version Dave tested. However, we have since addressed several bugs and made upgrades to the instrument.
Great to hear. Is this a firmware update I can apply?
@@EEVblog😀
sorry, I am afraid it is not a firmware update yet. But I can send you an updated sample if you like.
@@EEVblog
And the user can apply a firmware update with the new version.
Dave, please do more testing on this unit on your 2nd channel. Also please do more testing of "cheap" test gear!
That doesn't seem too bad for the price.
It's nice they used an 18650 in a holder instead of a custom lipo that will puff up in a year or two.
Puff up like a hollywood actress’ lips
1:18 Because Zotek is not a member of the TMA. Thank goodness we have non-monopoly manufacturers to supply us with illicit switchable probes.
Why are they illicit?
Hobby world stuff. 🥰
@@hoverbovver Big oscilloscope are trying to make switchable probes obsolete using some very dubious arguments (including "muh environmental crisis"). The biggest takeaway seems to be that they'll be able to sell more single range probes.
@@hoverbovver Jessica V is making reference to an April Fools video where it was said that switchable scope probes had been banned.
For anyone that is interested, after the latest firmware update it now boots into the mode it was in when you shut it down. it no longer defaults to oscilloscope mode.
Since the 10A range is essentially just a shunt over the mA sensing circuit, it's actually quite common for cheaper full-digital meters to show a reading in the mA range when attaching current to the 10A range. All the setting does is replace the mathematical scaling on the output value. Nothing to worry about. Teaches you to check twice what range you're in, especially when reading unexpected values.
Also, reviews of affordable measuring kit is definitely appreciated. Much more useful than teardowns of multi-thousand dollar gear.
Yes, I have a couple of meters that use two shunts in series and you can get confused on the mA an A settings since both appear to show a reading. You can fix this by simply blowing the fuse and the only the A terminal works, thus fixing your problem.
Same thing on lots of old instruments. Moving your probe to the 10x input doesn't change the indications, it just scales the signal.
Yes please more Low Budget Reviews, not everyone has the budget for such big equipment.
As someone on a shoestring budget, I'll chime in as someone who is always on the lookout for useable, cheap tools, since you asked. I don't know if you find the topic interesting yourself, but I would appreciate taking a look on more budget-friendly tools.
the fact its actually a removable 18650 and not a soldered on silver li-ion bag with no markings on it is great
i first thought "oh, rechargeable, so very limited life without modification."
but that is a really good implementation
only better way would be to put an easy to access door on it 😉
Right. One could swap it with a charged cell in a zip.
Great for us vape mod box users lol
It's quite amazing that we went from "Pocket" oscilloscopes from the 1970s and 1990s such as the Tektronix 200 series that cost thousands USD to less than 80 today!
I'm 64 and I dreamed of a device like that in the 70s. I think it's a great tool for the beginner or in my garage doing auto diagnostics. The price is unbeatable. I've worked with and owned many Fluke meters over the years and they ALL have quirks too, you just gotta get used to them. The scope function would be great for car audio hum tracking. If you run over it with the big ole truck you are not out that much money compared to a $1000 Fluke. I will probably buy one to play with.
70's? This tool at this price was a dream even 20 years ago.
I think it would be great in the shed for general automotive use
Newly launched ZT-703S (3 in 1)
1.All-in-One Device: Oscilloscope, signal generator, and multimeter.
2.High Precision: 50MHz bandwidth, 280MSa/s sampling rate.
3.Clear Display: 3.5-inch IPS color screen.
4.Ease of Use: Intuitive interface, user-friendly.
5.Portable Design: Compact, lightweight, ideal for field use.
It's absolutely amazing how if you don't over-advertise your product's specifications by 10x, suddenly Dave doesn't think it's absolute trash. Boggles the mind.
I mean, dont we all agree? If you know what you are buying, you at least wont be disappointed when you can plan ahead and decide if the device is for you.
Spent so many decades craving my own Tektronix o-scope, I'm totally jealous of today's young electronics hobbyists.
free trade baby
16:30 They don't have probe insert detection, so the meter has no way to tell if you have the probe in the A or mA socket. That's why you have to select the proper mode yourself. Physically disconnecting all the wrong sockets in each mode would be too expensive. Like with any normal DMM you could have the probe in the volts socket while having it switched to amps, and you will just get zero value, because the switch physically disconnects the volt socket. This meter doesn't have a physical switch.
Also they have put the sticker, because they cannot detect the probe in the amps socket while measuring voltage.
I agree with Dave that this is not acceptable. There are many solutions to this problem, some of which will be pretty cheap to implement. You dont need to physically disconnect everything for that.
Yeah but the point is it's bad design to have a meter that's capable of giving you a wildly wrong reading like this. I have not traced out the circuit to know exactly why it's doing this, but no meter design should deliberately give false readings.
Wouldn't it be easy enough to tell which one is powered and buzz like hell if it's the wrong one?
You probably don't need to electrically disconnect the wrong socket, just move the current mode selection buttons inside the socket so it automatically picks the right one when you insert a cable. That would also give them the ability to beep and put an even bigger DO NOT MEASURE VOLTAGE WITH THIS HOLE warning on the display whenever you plug something in :)
They don't need to detect where the probe is, just select which input they're measuring. They don't even need to switch the load to do this. Just use a relay of some type to select which current shunt that's being connected to the ADC. This would then show 0 A/mA when the wrong range is selected. This would be better than showing a completely bogus value with a large magnitude.
Thanks Dave, I love the review and ordered one immediately for my "on the road" toolbox.
My little scope works well for use on site. Drones and RC car issues. Works as a multimeter so don't have to carry both. I've only needed the scope function twice testing PWM and RF output. but nice to have. Other fliers that borrowed it liked it 2 of the group bought one. Can't have enough scopes. Also another time I used it for an FM transmitter I use for portable dive in movie nights and needed to find out what was up with it. Drive out somewhere dark and put up a screen if not a wall and make popcorn, eat licorice with a cooler full of pops and watch a double feature. Pop the projector on the roof plugged into a battery bank for 2-3 movies. FM transmitter plays the audio on an FM channel on everyone's radio. Invite friends or post on social for people to meet up.
Yes Dave! Mailbag, teardown and review all in one. Super! 🙂 👍
Can you imagine seeing this even 5 years ago? I've gotta think Dave has driven a LOT of development.
Looks handy to test sensors while out in the field. A bit disappointed that it is not fully cat rated.
Very handy to see this review.
The battery life is good enough for most jobs as mostly use my uniT clamp meter and voltage stick for standard stuff.
Regulations in UK force us to use sticks like the fluke T150!
If this multimeter was open source and reprogrammable, that would be a game changer and a magnitude closer to perfection
I think Dave started such a project some years ago, but it didn’t go beyond rough design and component picks. Just a multimeter though, no scope.
There's been several hanheld open source (or semi open with alternative community firmware) scopes, I got one from Seeed studio. Sadly they kinda died and after couple years no more updates.
"Stop testing current in voltage mode" LOL, well deserved sticker.
Loved the signal tracing lesson.
As someone who builds valve guitar and hifi projects, this is flipp'in amazing - I just wish it had an FFT freq res display, that would be simply off the chart useful.
Or some way to dump out the storage trace over the USB for post processing.
Whereas I love that bench oscilloscopes are available with function generators, FFT spectrum analysis, and enough inputs to handle proper valve amp biasing and plenty of diagnostics (sometimes simultaneously), the costs are certainly intimidating. Of the brands typically covered by Dave, only Rigol offers products meeting that general description for less than US$1k. Siglent, Rohde & Schwartz, and Keysight bench oscilloscopes cost between US$1k and US$2k with that array of features (of course, bandwidth is not a practical consideration for valve amp work in this era of oscilloscopes). That the most basic subset of that functionality can be covered by a handheld unit costing less than US$100 is pretty amazing.
Looks like it does what the specifications claim, unlike some other cheap scopes we've seen you test (I'm looking at you, Fnirsi!). This would be great in the tool bag I always bring when I go anywhere else to work on cars or things like that, you wouldn't need it very often but it's small enough to always be there when you do - it would replace the regular multimeter I have there now.
"...Charging your shoe phone..." lol 1965 says hello! Thanks for takin' the time to look at this gizmo!
They should monitor Dave's review and update the firmware to eliminate the possibility to go wrong, I love how Dave test it with professional equipment, fantastic test!
They sent it to him for review so I would assume they would take note of his ... review ??
@@peterfitzpatrick7032 indeed. Furthermore this was a prototype and not he final product yet
I've been trying it out past week. Very nice form factor and works great.
I just received mine and decided to put it to the test. My standard scopes are a Fluke 190-204 and a USB type from Pico. I don't remember the model, 4000 something. So this little guy is sharing space in my tool bag (I'm a mobile tech) with some fairly heavy hitters. I work on battery operated Industrial equipment. Anyways, I discovered a very funky signal on my 5 volt reference circuit, a suspiciously familiar pattern, exactly like what you'd expect from an ac motor controller phase. A very nice crisp thin trace on the display made it easy to see the issue. Turns out one of the motor cables was pinched and shorted to frame and wreaking havoc on the five volt circuit. Anywayyyyys! Very impressive display and performance from a $71 scope. As a side note, in the multimeter mode min max and average volts are constantly displayed. That is really really important for someone who works on equipment running on lead acid industrial batteries. I can't count how many times I've been stung by a battery that has a reasonable state of charge but falls on it's face or even goes open under a small load and recovers to a reasonable voltage in a split second. I wouldn't own a meter without a min/max feature, but this meter has it displayed constantly! I absolutely love that.
Like the info I was interested in the functionality of this scope and you nailed it 👍
It's amazing the great cheap gear you can get now 👍
I love that it uses an 18650.
Fairly clean design, the soldering is really agricultural tho'. Hand soldered ARM chip ??
"agricultural" LOL, I like that.
I remember someone doing some investigative journalism to figure out where cheap SD cards were made in China. (Might have been Andrew "bunnie" Huang.) They figured out that one "factory" was actually a farm building with chickens running around outside.
@@Gameboygenius Bunnie is a freaking legend in the Maker community 👍😆
@@edwardfletcher7790 Even my father (age 72) knows who Bunnie is.
MIT multi book 'how to hack an xbox' Bunnie. Bunnie is a lyrical genius. We're lucky to live in the same timeline.
One gotcha of this scope is that it's essentially a differential probe since it's not grounded UNLESS you connect it to PC, at which moment it suddenly becomes grounded. Can potentially make for some fireworks if operator is not careful.
For a DIY hobbyist this thing is pretty sweet honestly.
I like your evaluation of low-cost electronic meter
Thank you
You should put out your own portable oscilloscopes Dave, I'd totally buy it!
Nice review video
I quite like this one. If they let us muck around with the firmware and make customs mods (even without warrenty), this is an awesome product.
Definitely interested in affordable test gear for us home shop guys! Not looking for the cheapest item, but more decent quality gear in the home shop price range. Thanks and great video as always!
The last part "for charging your shoe phone" I just cracked right up 🙂
Nice info, keep it up, thanks :)
Looks really good. When I get a job again, I will definitely buy such a device.
Nice review - I would love to see Dave do a similar review on an Owon portable oscilloscope . It has a similar use case of having a small oscilloscope for use when travelling around but specs seem better and I would probably be more confidant of what it was telling me.
The EEVB gang has been burning up the Amazon search for this unit. Ha! Thanks for giving us a heads-up on it. Seems like a great addition to the go-box!
During the "A vs mA" misreading, I was screaming at my monitor "Dave, it's in the wrong mode dude!". Funny stuff. Been there, done that.
It shouldn't be possible to do that and get a wrong reading though.
@@EEVblog Actually at 17.03 after switching back to A range the meter did correctly display the right(ish) value of 11.0 mA . Probably a software bug in there somewhere. Acutally scratch that, I missed you switching to 100uA.
Oh I used the gold plated version of those probes for a long time. They are great for the price. Good cable, above good tips, low price. Highly recommend them.
5 hours of use between charges isn't too bad... In that price range, it's going to mainly be hobby use, so 5 hours will be several days usage at higher usage rates, and probably a month or 2 for most users who'll just use if for half an hour or so every few days.
It's not like these will be used for 8 hour work days in a lab situation.
I like it. Good review. 👍
And Dave gets the clearance wrong again (6:50) ...
- You *don't* need clearance between traces at the same voltage level. The screw can not be touched from the outside, and is far away from the Common trace
- You *dont* need clearance between Common and the *fused protected* Current trace (only between Common and the actual Current input socket)
- You need clearance between Common and Voltage input
There may be such issues, but you can't tell with such a short glimpse.
Okayyyy thanks for review
wow looks pretty cool. I may have to pick one of these up to have a real portable scope for basic uses
Nice little scope for the price, and review. The battery life could be upgraded with a flat pack battery, a 5 AH could fit in there
Good review. More low cost items please, but keep a reasonable perspective because we all know that a $80 scope can't be as good as a $2000 one or even as a $200 one.
I would have given my right arm for something like this as a teenage hobbyist back in the early 80's when to own an oscilloscope was merely a fantasy. For young makers today, just needing to check a signal is there and intact and check a few voltages, it is just the job. It may not be perfect , but looks like most of those issues are tweaks that could be easily fixed. One thing I don't like about all those Aneng meters is the convex display. Arggh. Why??
May have to pick one of these up. I had to toss out my 15 year old Craftsman DMM since the batteries corroded after moving from the old house to new house last year...and I really need to have a DMM and now an oscope in the home for all the projects and repairs I do.
Please test more of the low cost stuff. Pretty interesting how quickly things evolve in this price range these days. I'd appreciate a follow up on the Zotek ZT-702S.
Great review. Just ordered this thing from China. I plan to use it for simple home applications like: repair some electronics, electrical grid measurement, some simple electronics projects(low frequency). Despite all drawbacks, it's gonna be great upgrade from my 15$ (another zoyi) multimeter.🤗
it looks like an interesting device for that price. the times where you get mostly trash for cheap priced devices are definitively gone.
Yes please, more testing of cheap and even garbage tier gear. Not just because it's useful and sometimes you have to poke with the stick you've got, but also because it's entertaining 😁
Thank you !
Nice video, Dave. Please could you do more videos of such devices, or please tell us how to reversibly alter out modern light oscilloscopes in a cheap manner to prevent us blowing it (or attached equipment) up
Dave: "You get what you get and you don't get upset!" 😂👍😀👍
6:07 that screw looks like it bypasses most of the creepge distance from the input socket
Doesn't look good. You'd have to trace it out to see how those traces are actually used though. But your working assumption has to that it's poor layout.
I agree. It is very close to those traces. There needs to be a plastic washer underneath it.
They could "easily" fix it with a plastic/nylon screw. Still, not great design.
Should have an insulating washer under it, right?
I just bought one and love it.
Thanks for this video and all your other your style is impeccable! Any suggestions for a good started bench scope?
For basic automotive work I find it's great especially when checking for presence of control signals, I feel you get a lot of meter for such a low price - USB 3 charging very useful to me.
The mA problem is not exactly a problem. It is a point they may do better. But conflicts between the software settings and the hardware connections will often cause confusion. Another example is the x1/x10 probe attenuation, we need to use them properly.
According to comment replies made by Zotek on their firmware update video, the mA measuring issue is fixed now. Dave, I'd love to see you test the Owon handheld scopes, they are better than most, the range now has 40Mhz, 70Mhz, 100Mhz and 200Mhz models.
At 20:48 - talking trigger level. I've seen that on some of those cheap scopes and those had a way of calibrating. Check the manual :)
Hi, the old metex M80 that I had was doing the same thing with the mA/A range. It was an Intersil ICL7xxx based meter which served me fine until the LCD became unreadable due to age.
Please 🙏🏻 test more of these low cost products because some turn out to be decent quality products too!!! 😊
This from a hackability perspective is intriguing. The display was very responsive despite it's flaws. A follow-up video investigating that would be nice if you find anything at least.
Looks like a decent meter to have in my go-bag for those quick troubleshooting jobs, especially at that price range. Sorta thing I won't be too broken up if it gets left in an equipment shelter or yeeted off a tower or something. Especially after a firmware update or two to square away a couple of those quibbles.
Definitely good enough for the binary "do I have signal?" checks.
For me, it may be worth it because I can leave it in the vehicle 24/7 without waking up over it.
For me, I have two kinds of measurements: is it there? And is it right?
These tools are good for is it there checks. If it's not right, I replace the part as it's not usually field serviceable.
Thought so also. But it is unresponsive and eats 2600mah battery real fast even when i just use it for basic multimeter tasks. Got a little dso 154pro and made 3d printed case for it. So far so good. Multimeter and oscilloscope combo is a neat idea but in practice i found it is be better to have it separate. So at least for now in the 40-60$ price range you can get a decent little oscilloscope and compact multimeter with some degree of safety as separate devices or 2 in 1 but with serious compromises.
Lucky ZOTEK getting the free (beta?) testing
It looks very interesting. Now EEVBlog can make a on the road video to check out the Solar generation rail tracks in Europe…😂!
For a cheaper all-in-one tester, it looks good. I would also not use it for high voltage testing or really anything that needed super precision, but certainly worth a look as a secondary meter to keep around. Amazon has it for $76, but is charging about $25 shipping (USD).
Heck I'm in. I'll pick one up when they are in stock.
my astroai DT132A multimeter (which I'm actually pretty happy with for the price) also suffers from that incorrect amp reading design. it's an obvious misuse case they probably should account for in the future. I'm pretty sure the DT132A uses the same chipset as this meter or at least a very similar chipset and so comes similar issues.
29:30 "For charging shoe phones". Classic Get Smart reference 🤣
The fact you can buy a small scope for the price of a half decent multimeter these days is just amazing. As a student I would be thrilled to have one of these back in the day. I couldn't even afford the basic 20 MHz Hameg analog scope...
I think the trigger thing is maybe also dependent on the divs hysteresis which it does not display. May be why it looses trigger.
For the price it look as very nice budget meter. Would like configurable multimeter display mode with big digits as Dave said. LoZ mode presence would be nice too, but then this meter probably would cost $30 more. Possibility to lit up white LEDs in diode mode is a big plus. You don't need someting separate for LED strip testing or when you have no idea are LED itself is dead or something behind it and don't want to solder the LED out. Oscilloscope is very basic and only for low frequencies. However for fast PWM or other control signal presence check on field it is fine. LOL-ed hard on camel toe glitch for saw signal at 24:56. In short - for casual repairs and DIY this device is fine enough.
When I saw the scopemeter, I expected a completely shared front end with all ranges etc. So the scope can examine the exact mains waveform or measure microamp waveforms.
Excellent.
I liked this little oscilloscope.:) Will give it a go, is good to be in the emergency bag
I like the meter's internal construction and apart from the obvious screwup at 6:50, I'd say it's okay, you could compare the meter part against the UT61E+.
Meter display, meh. 7-seg please!
I like the probes, though they could use some insulating covers revealing the end of the tip.
The current meter, it's pure craziness! 1.1A on a mA socket with 10mA going through it? Damnit, is there no socket detection on this thing? Hope they fix that, unless they make a firmware update that locks you off basic functionality unless you pay them ransom, like Rossmann recently mentioned.
Calibration port under the cover next to the USB3 port is pretty clever, I like it. The inaccessible BNC socket, on the other hand, is not.
21:17 I can imagine Fran getting more and more pissed off at this thing.
5MHz bandwidth? Fine for power grid and audio applications. Some of those old analog Tek scopes went that far and no one complained, LOL.
I like the separation of grounds. Imagine measuring the interphase voltage on a 3-phase grid and touching that BNC sleeve... Ouch!
C'mon, what's with these people who buy a good quality meter and don't know it has a fuse (often not just one) in it, that can get blown?
I wonder if it would be possible for products like this to have the ability to use the multi-meter inputs usable as differential probes. It could be useful even at even a tenth of the bandwidth.
This is a great little device for beginners. I would have bought one if it had been available when i was looking.
Great review! I would like to purchase ZT703S for myself, but it is not available for order. I don't really need to check the diodes, but voltage measurement and waveform verification are very much in demand. My thanks for your work! If the Chinese do not respond to my request for ZT703S, I will order one.
I bought a similar one from RuoShui/Victor (270) and I've seen a suspiciously similar one branded OWON and another branded Hantek, with versions claiming 2 oscilloscope channels with max frequency of 30MHz, 70MHz, 100MHz and 200MHz, and variants with a signal generator, they all seem to be built off similar software and hardware. Mine also has a warning about making sure you've connected everything properly in current mode that appears _every_ time you switch to it.
Might be worth getting these clones and finding out if they're better/worse/the same.
Another cool feature that might be nice would be to chart the digital meter value on the screen, like a scope or chart recorder. It already is printing the values to the screen as digits so why not add a trace plot? I get why it's so common that these devices have only 1 scope channel, but I'd pay a few bucks more for a 2 channel even if using 2 channels cut the bw in half so long as using just the 1 channel went back to full bw.
One channel on the BNC, the other on the multimeter leads - just software to implement (admittedly probably externally limited DMM probe bandwidth)
@@paulstubbs7678 Or at least an external trigger using the volt/ohm probe jack.
As for the ammeter weirdness... I have a Snap-On multimeter, probably 10 years old now, that does the exact same thing. I've made many screw-ups by having the meter in amps mode, and having the leads in the milliamps jack. It still measures it, but the reading is always way off. Not sure why.
Burst out laughing when you brought out the Crocodile Dundee knife. Yeah, that should get it open...
oh wow a manual that is worth something, I haven't seen one of those in a while
A lot of multimeters have that mA/A issue. It's quite common, I'm surprised by your surprise 🙂
[chuckle] As soon as you said "I can't give it a thumbs up", RUclips played a rainbow animation on the thumbs up button for the video.
6:46 That screw should have a nylon washer underneath it. Its very close to those traces. Especially the left one where your plastic yellow pointer is pointing.
I recon you need a perspective for what alternatives there is out there.. quite a few multimeter/oscillioscope on the market these days, around the 100 dollar mark, that seems way superior on specs.
I wondered about buying an Owon version in first half of 2021 so a few years back.
It was a HDS242 at just over 100 USD with incl-. 25% VAT and shipping..
Its an 20.000 count, 2ch. 250Msa/s - 40MHz, 10.000Wfs also with 18650 usecase though 2x and 3.5" screen. but 8bits and merely 8k record length.
there is also other HDS-models (3-1) going to 100Mhz & 500Msa/s and models with an inbuld signal generator (labelled with an "S" in the modelname) but they are around 200US, there is also tons of other models of this exact scope/multimeter (HDS class) but with names that aint that wellknown here in the west, like fx Victor and others.. they have an orange sleeve or an Green sleeve, instead of Owons blue variant.. not sure who makes it, .. as I doubt its Owon when other brands also have a version of this exact scope/multimeter..
but great video.. what I wanna see.. taking a look at new tech hitting the market.
I would like to have seen that oscilloscope connected to high voltage, such as the gate of a mosfet of a switching power supply. 😉
Would it make any difference as it is essentially a differential probe without any ground reference?
Very nice
It would be interesting if they add a graph in multimeter mode, instead of the "scale" on the top. Way better use of that display.
I can see this being nice for automotive use, just wish they had two channels or atleast a trigger channel.