My digital oscilloscope (test, teardown, fix)
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- Опубліковано 1 лют 2025
- Today let's see what's inside my DSO FNIRSI PRO handheld digital oscilloscope (5 MHz, 20 MSps). It was meant to be a short peek inside, but I ended up making a review, identifying all important components in it and also fixing the AC-only mode that for some reason didn't work.
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(14:26) - And I thought I was the only one to do that !
When you take apart and then put back together many cheap things like this, you quickly learn how easy it is to "strip the existing thread"
No one seems to comment on this at all.
All those digital multimeter reviews where the battery compartment lid has self-tapping screws which are oh so easy to cross-thread if you do not do carefully with a keen ear and a delicate hand.
Sir! You know exactly what I am talking about.
I wanted to make a video myself for so long about this and even now I guess at least half of your audience do not even understand the significance of your stirling, perfect, fantastic instructions.
Now we have to meet.
It was destined to be.
>
Here, get a like, you deserve it
Someone ask me if I'm to dumb to put the screw back in as I did the trick :(
I always thought I was the only person that did that. I feel like I'm finding my people now!
I do that too!
I also tighten opposite corner/side screws, it helps get better alignment!
A pro-tip: when screwing in any screw, first put it in place and turn it backwards until you feel it clicked into the first loop of the threading ;)
Injust bought the same one.
My input resistance measured 996k ohms
The capacitor you asked to measure is 945nF
Good job, thanks for the video!
Maybe someone could look at the values of the input resistors in their unit.
The one he has might be different.
I ordered one from Aliexpress a few weeks ago. Works perfect. Capacitor is good. Board is clean, no after-production intervention. Seems well built. Connected it to 220v without setting the probe to 10x and it didn't burn. Readings were wrong, but it survived. Very handy in testing the waveform of my crappy gasoline generator. Highly recommended.
Quick aliexpress search, it's just 36 euro right now, including shipping. Honestly, i'm amazed by the build quallity, and judging by the look of the cap and ss relay, it seems that it was defective from the factory, and somebody replaced the relay and cap by hand, as all other smds are obviously not hand soldered. Also, about the short of the capacitor, Dave from EEVBlog has a video about multilayer ceramic caps, especially smd ones, which tend to go short if they or the board they're soldered to is bent, so it may have been a poor solder job that has put tension on the cap and it shorted out, for example: soldering one side and pushing the other side with tweezers while heating it up, and by reflowing it you likely removed the short. Should be replaced imo. Thinking of getting one for myself, it seems great and it's great value for the money, especially for hobby electronics.
I just did a Google shopping search for "DSO FNIRSI PRO". They're questionably cheap (but for some odd reason seem to be working).
Can you please give us the link for alliexepress of oscillator
@@xnetworkDEVILx not really, just type "Dso Fnirsi Pro"
The same manufacturer (and in the "FNIRSI Official Store" on AliExpress) has a higher-spec model that also looks very good for the money, at £61 ($71/€66 ... damn, was that huge exchange rate shift over the past 3 weeks due to COVID-19‽).
€36 FNIRSI PRO: 5MHz, 20MS/s, 1200/1500mAh Li-Ion.
€66 FNIRSI-5012H: 100MHz, 500MS/s, 3000mAh Li-Ion, and is supplied with a "proper" 100MHz probe rather than dual croc-clips :)
Most of the rest of the specs appear to be largely the same - where they supply specs for both models, at least.
There's also a FNIRSI-1C15 110MHz 500MS/s model for £63, but I don't have time right now to see how that compares!
As far as I can tell, these are all better value than, for example, the Hantek 6022BE USB/PC-connected budget oscilloscope...
@Против Глобал you do understand that it's 10x the price? Not everyone will use it professionally, and it will never pay itself off. Sure, if you can afford it, go for it. But for hobby purposes, it'll work just fine.
this is a very thorough scope teardown, much appreciation
The solder bridge on this capacitor was easily visible. It was once my job to fix such manufacturing defects and i have seen lots of identical problems :)
Thank you Diode! Waiting for another video on oscilloscopes!
4.26 uF and 406 kOhm when set to DC. When set to AC the resistance keep rising and I just stopped at 25 Mohm
Same for me. Still strange that the rated input impedance is 1M by the manufacturer and that several others have different readings in DC mode too.
That's a pretty neat little ADC. It surprised me that it had something like that...Usually these little hand held things give you audio bandwidths..Wonder how this holds up? It says 5Mhz The analogue ip of the ADC is fed directly from that op amp which is optimised for video, so the 5Mhz is spot on. Compared to the careful design of a 'proper' scope the i/p looks crazy simple but should be OK at these frequencies.
Great fun though and the display looks nice and colourful. A step nearer the thing we have been waiting for for 70 years...Soon...Maybe..
9:12 = All flash memories used in microcontroller have a high voltage generator (about 9V 10 12V) used to erase the flash. Its mostly a charge pump boost type. Usually, it is not shown in block diagram.
It seems to have a discrete configurable attenuator at the input followed by a fixed high gain opamp. The atennuation value is selected with solid state relays.
things sure are getting better every day...thanks :)
Another nice video from you i like your kind of funny english. You seem to be really skilled in eletric appliances
Good video. This looks like a much more usable product that other low cost digital oscilliscopes I have seen.
Have you checked out my Hantek IDSO 1070A? For 150 Euro you get 2 channels up to 70MHz, Wifi and USB connectivity and 2 pretty good probes. You can use it with PC or Android / IOS phone / tablet
I am very happy with it and after 6 months of active use I can recommend it, for it's value you get REALLY good scope!
Check it out.
Vít Cenek
At 4/5x the price the Hantek falls in a different category. That doesn’t mean it isn’t very good value for its price but just that it’s not an alternative for someone with a budget for the DSO in the video.
@@Conservator. Yes, I agree. But you get a point. Thanks for your opinion.
Vít Cenek 👍
@Heads Mess USB scopes are great for working on things such as automobiles. You need something mobile and battery powered if you want to watch circuits while test driving. Being able to save waveforms so you can analyze when you get back to the shop is the cat's meow.
I would loved to have had that when I started electronics as a kid.
Most likely the capacitor was shorted but the heat from your soldering iron fixed it. I have seen this in many ceramic capacitors where they have faults but you warm them up with a hot air gun or an iron and suddenly the short resolves.
Those Data sheets make all the difference, thanks!
5:10 Watch the battery indicator. Never seen such a broken one before. Does the voltage fluctuate THIS much?
I didn't even notice this :). Maybe the voltage really fluctuates as the microcontroller power consumption fluctuates. But more likely the indicator is poorly designed. But it's not the most important part of the oscilloscope.
@@DiodeGoneWild i think it just jumps from 49% to 50% voltage, and thats why it flicker
Nice review video 👍
Nicely done
The short circuit between the capacitor terminals was probably caused by ionic contamination on the PCB.
Heating the area and resoldering the component make the problem disappear, but it may come back later if the contaminants are not properly removed by cleaning.
I've seen those MLCC short at a few hundred ohms, instead of a "short" circuit like 0.1 ohm.
In addition, sometimes it comes and goes with heat... :P
That phantom shorting smd capacitor happened to me once, when I removed it from the PCB it measured short for a while then self healed itself. Very bizarre.
If people complain about the 50mV input sensivity being too unsensitive....the video amplifier has an 8k/8k unity gain configuration but gain can be raised by large numbers if the resistor facing away from the A/D-converter is replaced by a smaller one (like 800 Ohms, will give 5mV sensivity or 80 Ohms will give 500uV per unit). Have to see if the caps will also have to be changed (linearity between low/high frequencies, I suppose it will) but for audio purposes it will be a great option if one has to measure noise levels or electric guitar signals.
I have tried a trimmer with 80 ohms...works okay but offset of the opamp pulls the y-axis down. After calibration no useful measurement can be done. Calibration takes like a minute or so.
Using an 800 ohms trim works better! Calibration still okay and offset okay too :-)
Wondering why the slower versions of this cheap oscilloscope can handle 5mV....maybe they used a gain of 10 and then had to limit bandwidth in favor of that opamp? This version uses a gain of only 1 and therefore frequency response of the opamp is better?
But why does the calibration not work for a gain of 100 ?
Are there better options for input circuitry? Maybe a different opamp? Any offers?
Maybe I omit all this input circuitry and make an external preamp for it...a clean booster for dso :-) No offset, high gain :-)
Dobri populodni!
You seem to have increased the timebase on your voice from when you first started doing videos Dan! lol
Good idea it makes your videos even more addictive!
My girlfriend is Slovak and she says she has never ever heard a Czech man speak English like you do!
You actually sound like you come from the Scottish Islands!
If i had a pound for every time you say "basiccccaaallllyy" i would be a millionaire lol
The user manual was so small printed: I needed a magnifier to read it.
So I made one on A5 format for easy book format printing!
just tried it and it's 402kohm for me too... it works fine but I'm a bit disappointed (the +300mah compensate a bit haha)
16:02 It looks to me like switching to AC coupling affects the amplitude of the displayed waveform.
I got one similar. The input impedeance measured 4M Ohm.
At my high school I have 2 oscilloscopes...
A small one and vintage, probably from the 60s
And another one being a larger one and looking more modern, probably from the 80s or 90s.
Both being a CRT topology.
That might have been worthy to buy, but the 400k input impedance is a show stopper for me, it won't work properly with 1:10 probes, just like the "legendary" USSR N313 mini scope, which is very cute, but quite useless. Also the divider is compensated with fixed capacitors, they should've used trimmer caps there. BUT, for 36EUR, it might worth a try to fix these design issues, with a bodged-in daughter board to replace the Y input circuitry.
The input attenuator stage of that scope needs to be redesigned to have 1 Mohms resistance on AC /and/ DC coupling. Only then a 10x probe will work properly. Would be interesting to do that...
I'va a similar one with an external AC/DC switch and it measures on DC 0,9 MΩ
The input coupling capacitor in my unit is 5.5 Uf
Mine is only measuring AC, doesn't react on DC signals. I think it has same or similar problem, I will check it, thank you. :)
I fixed mine also, thank you dude!
Hello! I have a very similar digital oscilloscope and the impedance I measure on the input BNC connector of my unit is: 1.312 MegOhms. I hope that this helps you.
Those batteries are available in all sorts of sizes and capacities. Most of them are made for RC drones and offer a very high discharge current. Those might not be the safest ones to use;)
How do I compensate a probe on this oscilloscope without the 1 kHz calibration output?
I have this one, not great , not terrible. Best for simple projects.
Hi, I love your videos. They're very informative. Can you also make videos on how to check amplifier output via that oscilloscope?
I have an oscilloscope very similar to this, but its like the original version of this oscilloscope. It has a 5Ah battery, more functions, a grammatically correct manual and better build quality. my input resistance is 1 mega ohm.
post your oscilloscope
Excellent video!
Would be interesting to see a youtube video on comparison between the cheap pocket oscilloscopes - DSO138 vs DSO150 vs DSO188 vs DSO068!
No one seems to have done a youtube video on it yet!
Considering buying one but the one you have the DSO188 looks the best with the widest signal range?
I recently purchased the same oscilloscope.
The input impedance was 406k ohms.
Try to run DOOM on it...
Duke Nukem 3d works perfectly at 60fps on it!
>;o)
same specs for mine. 400k resistance. seems to follow the same approach of bob davis's nuts and volts arduino oscilloscope. this one uses gd32f103 which is a cheap clone of stm32f103, it uses a TLC5510 which is 20MSps adc, i wish they used the 40MSps one which is the TLC5540. it's good enough for hobby electronics such as audio frequencies to smps switching frequencies even up to 1.7MHz switching frequencies of some ultrasonic humidifiers. pretty handy little widget. and yes i also took it apart after unboxing and testing it. even the input smd capacitor has the same capacitance.
Hope your doing well during this covid 19 outbreak. Stay safe
You talk funny. Very knowledgeable. I enjoy your Videos.
I have mixed feelings about that MOS relay shorting out a possibly charged 4.7uF cap. At least there should be a 10ohm resistor in series with the switch. I don't know what is the lower part of the voltage divider, but it wouldn't introduce any noticeable error, and this device isn't for precision measurement anyways.
Can someone send him soldering station?
A plumber gas torch would be more appropriate for the job :) Also I'm surprised to see the IC markings haven't been scrapped. Are they slacking now?
No, the flash chip certainly does not contain the software/firmware. Because GD32 (STM32F103 clone) doesn't actually have much RAM and is not well suited to execute program from RAM, but it has plenty of builtin flash. It also has no capability to execute software from external flash directly. It's also not strictly needed to store settings, there's plenty of flash on the microcontroller for that. It's there to store waveform captures for sure.
هل فيه مشاكل بدون إضافات أو تغيِّرات ؟؟
I wish i was as smart, very nice videos
The GD32F130 is hw & sw compatible with the STM32F130. The choice is a bit weird as for ~ 0.5 $ more they could have used GD32F3xx (or STM32f3x) which as several 5Mhz DAC inside the chip.
Try again, there exists no STM32F130. There does exist GD32F130 which is a 48MHz micro with smaller amounts of flash i think 16/32KB and SRAM of like 4KB, very cost optimised. Of course rival STM32 parts would be the L0 line with an entirely different core.
You're thinking of STM32F103 and indeed Diode has misread the chip or has been confused by a typographic error in the datasheet, it says GD32F103 on the chip.
I thought that GD32F3xx were vaporware, but i checked just now and they are available. Colour me surprised.
@@SianaGearz And they do contain 2 (3?) 5Mhz ADC .
Nice work
I'd replace the AC coupling capacitor anyway, just to play it safe.
I wonder how similar the 20€ scopes on eBay are, it looks more or less the same but it has 4 buttons and a knob instead. Assuming similar build quality I could definitely use one for the occasional times I need a scope for checking signals, without needing to be completely accurate
That sounds like the DSO Shell. I can't answer for the build quality as I made mine myself from a kit 😉 It's very prone to noise pickup - this is a recurrent theme in online reviews of the unit, so it's not necessarily my fault!
Hi, Please repair some defective multimeters there are not many videos out there.
I appreciate your work.
The input capacitor I would say 100v and size is more important than value. .005 to .1 uf highest value that will fit in the location.
I see one like it for 15 dollars. I'm buying one. don't care if its not fluke or rigol quality, I'm not a rocket scientist ,is good enough.
That's a very nice little scope, i would not expect it to be accurate with a composite video input, but it should display most of the waveform fine :-D
Digital scopes have some restrictions due to sample rate and resolution bits, not forgetting having enough memory to store it.
Analog scopes are my favorites, i am used to them :-D
That is not a composite video input socket it is a BNC connector they are either 50 or 75 ohms impedance
@@jasnic2131 i'm sure Mr. ZX is quite aware. He repairs things which have composite video out though.
Also the input impedance is not determined by the socket, but by device circuitry, and in this case, it's 1M claimed, 400K actual.
Hey, so they added a mechanical switch there? Sick. Myself whenever messing with any LCMs I always add a shutdown sequence triggered by a button or via the UI, which puts the LCM into powerdown, waits for one's driver supply to discharge, then disables any PSUs if used and finally puts the MCU to sleep because why not :)
What does the input part of the oscilloscope look like, which changes the voltage range using ballasts?
Nice video
What’s the site you are using for data sheet
I just google them ;)
HI! :) that relay below the capacitor (visible at 11:33) top line reads CPC100 something.... my fnirsi pro has a different relay!
the component on my board is "BETEC Y214S 1333" (the "1" in 1333 is hard to read and might be incorrect)
HTH, pls reply if you managed to get single trigger mode working!
measuring resistance on the probe socket gives me an initial reading of several Megaohms that increases steadily. i'm no expert, i'm using the resistance setting on a fluke 27/FM, which only has one setting for ohms.
14:25 "cowuuhn-uhterr" music to my ears, built a lot of speech synthesizers, thoroughly enjoyed the watch.
great video friend
this got me curious: 16:50 could you explain how this network divider works?
I have AARONTEK oscilloscope which has Infinity ohm in input. And when it is on, it has 1,3 mega ohms.
Neat! Just pu one into my shopping cart!
Those screens. I managed to break an identical ribbon connector fixing my dashcam - theyre such a pain.
Can you do or review a contactless thermometer
Hi, did you try to measure DC voltage with this oscilloscope? I tried and have real trouble to do so. For starters if you short the input (zero signal) in the "normal" mode it shows nothing until you press "STOP" button at which point it shows a strange non-zero value. In the "AUTO" mode it does not show the zero value, but jumps positive and/or negative as you go through the ranges. And when I connected a battery to the input to measure the voltage (DC mode) it shows a complete garbage, not even close to the actual voltage. Does anyone has this problem?
7;23 which site of this ? It's hard found short coded things
At 1:55/1:58, the black clip springs off. What are you measuring? :) "It doesn't do much." You can even hear it. :)
Of course it didn't measure. I reconnected it off camera after realizing it.
i wonder if you can help me get the single trigger mode working.
i have some AAA batteries in series with a switch and an LED. when the switch is closed, the LED lights. in "auto" mode, the fnirsi pro displays the level of voltage. i want to observe the moment the voltage jumps from 0V to +V. i set the trigger mode to single, press the button, the display remains blank.
can it measure wavelength and voltage at a point.. or is it only good at uniform signals like sine and square wave... and gives you generic data like its frequency and peak and average voltages
Can you review Dso138 oscilloscope
I don't think that the root of the problem was the capacitor but a pull down resistor instead which was absent and probably was shorted out before you started desoldering
probably first time i've seen soldering gun being used on smd
How about 7mhz signal this oscilloscope can measure this signal ?
any ideas to increase the impedance?
modrá hranatá trafopájka? to ani nevím, že takové jsou, mám dvě šedé
Jsou. Nebo spíš byly. Je to 75VA. Já taky mám ještě jednu stejnou akorát bílou (nebo světle šedou?). A pak ještě oranžovou větší. Myslím že 100VA.
How to solve low voltage problem in home about 220 to 180 volts stepping down for 4 seconds in some time plz make video or I should use fan capacitor to stabilize voltage
Is it really 5 MHz bandwidth? Usually these hand held scopes exaggerate their capabilities some.
@@kingflockthewarrior202 even 420 kHz isn't bad. I have a couple of the little portable scopes. They're fun.
thanks man!
hello waiting for the second video about how to use it safely
Came for the review, stayed for his accent
Does this osc. have some output to computer to view the curve?
I think the USB connector is just fot charging. A camera is the output that gets the curve to a computer :).
@@DiodeGoneWild I have similar osc. with USB and RS-232 output (csv format) but did not yet try it. The curve is created with appl. named gnuplot.
I'm guessing you're a Welsh Italian ?....great vids !
He's Czech I think.
Yes, he is from czech republic
Yes, Czech, but he may learn english by somebody from India.
@@goc9000 I used to work with a super smart guy who was Welsh German, he had an odd accent too !
@@michaelturner4457 Hold on I'll Czech...
The micro runs at only 72 MHz! Single core ARM!!! How can they run the micro to process the 8 bit data so quickly? I was working on a 70Mhz 16bit oscilloscope but I was constantly forced to use FPGA to dump data into ram before processing. No microcontroller seems to be able to handle it. Now seeing its possible with an ARM, I really want to get a raspberry pi to work with my ADC chips. RasPi zeros cost only 5 dollars now and have a sufficiently fast clock.
I would imagine the data is transferred into a circular RAM buffer by DMA, that's the probably the only bit that needs to be fast. If the scope is operating at a slow timebase they could switch to a slower timer driven sample rate and just discard samples to keep the memory footprint reasonable. I'm surprised they didn't just totally cheat and use one of of the ADCs in the micro.
@@xequals-pc1wl Same! Thanks for the information it is helpful. I only have experience programming in modified C and haven't programmed any real STM32 or fpgas. I really hope some Arduino boards I have will support DMA. Also, I don't DMA can magically increase sample rate above the max clock of MCU
@@leozendo3500 Ok, without a schematic I'm totally guessing, but assuming the micro is clocked by that 20MHz oscillator and the ADC is clocked at 5MHz using one of the micro's timers then it could/should/maybe work out. I only program in 'C', assembly language is dead :)
@@xequals-pc1wl Very nice. That gives me good reason to spend more time coding in c. But still without things like Arduino librarys it's a time consuming and brain bursting hobby.
@@xequals-pc1wl The XTAL is 20 MHz, but there is a complex clock system in that chip, it is most likely not run on 20 MHz, but more.
That ADC is 20 MSPS only, so it is possible to fetch the ADC data into RAM with DMA transfers, then the main thread will display a portion of it. It will certainly not display all the samples, maybe on a "DMA completed" interrupt handler they execute a fast trigger condition search, then mark the section of the buffer where that portion is, then they start another DMA transfer with a second buffer. So probably they aren't sampling continuously. You probably can't capture a rarely occuring glitch with this setup, but it is certainly doable to display every fewth section of the waveform.
Is the specs of this dso enough for analysing DC power supplies?
5MHz / 20MSps is kind of enough to analyze switching power supplies. They run mostly below 200 kHz so you get about 100 or more samples per period. You can display the waveform quite nicely, but you don't have a huge headroom to accurately measure short duty cycles. Also some short transients during switching may not be visible.
Perfect
Cool 👍👌💯🌹
Maybe someone could look at the values of the input resistors in their unit.
The one he has might be different.
no microSD or USB port for flash memory :(
7:25 omg how did you find it ...website name please !?
www.s-manuals.com/smd
The next make a video about optocouplers
Man i have that soldering gun from my old grandfather i have it in white color Can you open that soldering gun for my and video because my light sometimes dosent work please open it for my on video i love your videos
pleaseeeeeee thanks man.
Throw it away and buy a proper soldering iron. Seriously.
@@johncoops6897 :)))))))))))))))
that one is "proper", not the "proper soldering gun". seriously! :D
@@miftosaurus - random comment is random. Are you trying to make a joke or a comment or a suggestion or what?
@@johncoops6897 so, you see this soldering gun for the first time ever?
i use it for almost 40 years, and most of eastern european technicians AND hobbysts use them for more than that.
DGW seem to be one of masters of that gun, so, for him, THIS is the "proper soldering gun".
for us, a soldering iron (temperature controlled or not, or an hot air station) is just a "secondary device", for those rare times we don't have the soldering gun working.
or is way too strong for 1005-size parts. :)
@@miftosaurus - I've been working on electronics for at LEAST 10 years longer than you have, and I've owned those "guns" in the past, along with many other different kinds of guns. I know exactly what that kind of gun is, exactly what it is best used for, and how to use it.
The gun is not a "Eastern European" design, they were very common everywhere in the world since what, the 1950's? Fundamentally they are a crude predecessor to the English "Scope" irons that use a trigger to push a carbon bush to provide heat directly to the tip. The Scope is a considerable improvement to the "gun" style since there is much less thermal lag, so providing much better (manual) heat control.
However it's 2021 now, and such clunky old crude devices aren't really needed for most tasks. A decent 60/75W temperature controlled iron has enough punch to not require a large thermal mass, and having temperature control makes it much more reliable for fine copper tracks, even with through-hole components.
If I need to solder any crazy-big stuff, I drag out a massive 200W 240V non-controlled Weller (designed for guttering and lead windows), or even use a old-school solid copper pyramid style heated with a butane flame. Even bigger than that, it's a Mapp Gas flame and sweating or brazing....
For medium work, I'd use my Scope which is 150W manual control and plenty of grunt for valve radios, big wring bushes, etc. I threw my guns away a long time ago, as they are a cheap and poor solution to a simple problem that other soldering products can perform much better.
we nreed to make the second video how use the small ascilloscop seyfly
You should get a proper soldering iron for the task.
I think he knows what he's doing ;)
Poking the internals with metal screwdriver before unplugging the battery makes my jaw drop on the ground lol.