My digital oscilloscope (test, teardown, fix) 

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!

(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. >

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.

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 :)

this is a very thorough scope teardown, much appreciation

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..

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

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.

I would loved to have had that when I started electronics as a kid.

Thank you Diode! Waiting for another video on oscilloscopes!

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.

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.

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.

Another nice video from you i like your kind of funny english. You seem to be really skilled in eletric appliances

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

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 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.

Those Data sheets make all the difference, thanks!

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)

Good video. This looks like a much more usable product that other low cost digital oscilliscopes I have seen.

I got one similar. The input impedeance measured 4M Ohm.

5:10 Watch the battery indicator. Never seen such a broken one before. Does the voltage fluctuate THIS much?

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.

The input coupling capacitor in my unit is 5.5 Uf

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;)

Nicely done

How do I compensate a probe on this oscilloscope without the 1 kHz calibration output?

16:02 It looks to me like switching to AC coupling affects the amplitude of the displayed waveform.

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'va a similar one with an external AC/DC switch and it measures on DC 0,9 MΩ

Try to run DOOM on it...

هل فيه مشاكل بدون إضافات أو تغيِّرات ؟؟

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.

Nice review video 👍

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

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...

things sure are getting better every day...thanks :)

Hi, Please repair some defective multimeters there are not many videos out there. I appreciate your work.

Can someone send him soldering station?

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.

I have this one, not great , not terrible. Best for simple projects.

probably first time i've seen soldering gun being used on smd

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.

I wish i was as smart, very nice videos

I recently purchased the same oscilloscope. The input impedance was 406k ohms.

I'd replace the AC coupling capacitor anyway, just to play it safe.

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?

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.

Hi, I love your videos. They're very informative. Can you also make videos on how to check amplifier output via that oscilloscope?

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.

Those screens. I managed to break an identical ribbon connector fixing my dashcam - theyre such a pain.

7;23 which site of this ? It's hard found short coded things

Came for the review, stayed for his accent

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?

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.

Poking the internals with metal screwdriver before unplugging the battery makes my jaw drop on the ground lol.

How about 7mhz signal this oscilloscope can measure this signal ?

I have AARONTEK oscilloscope which has Infinity ohm in input. And when it is on, it has 1,3 mega ohms.

You talk funny. Very knowledgeable. I enjoy your Videos.

Can you review Dso138 oscilloscope

Hope your doing well during this covid 19 outbreak. Stay safe

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.

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!

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.

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

modrá hranatá trafopájka? to ani nevím, že takové jsou, mám dvě šedé

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 :)

Excellent video!

Maybe someone could look at the values of the input resistors in their unit. The one he has might be different.

Neat! Just pu one into my shopping cart!

great video friend this got me curious: 16:50 could you explain how this network divider works?

What does the input part of the oscilloscope look like, which changes the voltage range using ballasts?

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

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

Nice work

Nice video What’s the site you are using for data sheet

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

Is it really 5 MHz bandwidth? Usually these hand held scopes exaggerate their capabilities some.

hello waiting for the second video about how to use it safely

no microSD or USB port for flash memory :(

a gdzie jest kot :) pozdrawiam z Polski

The next make a video about optocouplers

That microcontroller is a knockoff of STM32F103 which is also found in the Blue Pill devboard. It's very popular, all over ebay and aliexpress.

any ideas to increase the impedance?

I'm guessing you're a Welsh Italian ?....great vids !

thanks man!

anyone have this firmware osciloscope? have my blank

At 1:55/1:58, the black clip springs off. What are you measuring? :) "It doesn't do much." You can even hear it. :)

Perfect

we nreed to make the second video how use the small ascilloscop seyfly

Can you do or review a contactless thermometer

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

Using a external high speed ADC and high bandwidth OpAmp? Impressive, but I think they've copied this circuit from a standard handheld Oscilloscope design and somehow managed to reduce board costs. But not paying attention to details like the input probe impedance reduces its value as a measurement instrument.

7:25 omg how did you find it ...website name please !?

4.00 uF and 406 kOhm for me

I have similar one DANIU brand that claims 100mHz lol. But it is quite dodgy, but ok for me because Im poor, and better this than none. Fave from eevblog has a video about this one.