Build an Oscilloscope for £15 the DSO138

Here I build an oscilloscope from a kit - and have to repair it after 10 seconds. though it was only one dodgy component. rare event.
this oscilloscope was donated by Banggood.com here is the link bit.ly/2bMsPeL
all music use within this video was made by markus fuller

[@fulviopicecchi4310]

It's a pleasure to see your work and listen to your explanations! You're great!

[@otissumnerbrown]

Thanks for your excellent report. Truly requires a skilled person to build it. Thanks for the Surface Mount Review. Very helpful.

[@myownwebsite0000]

There are several cheap oscilloscopes..very useful..almost mandatory... they are very great and useful for clean signals.. but you will have to use your ears for high frequency noise and oscillations .. and then use a small capacitor to ground most of any possible noise heard.

[@Solimara]

You Sir, are a wizard... I need to work a long time on my soldering before I can dream this big.

[@nodrogawson963]

Excellent video, full of useful and helpful hints and tips exactly what I wanted to know about building the oscilloscope. Thank you for sharing, much appreciated.

[@markusfuller]

Thank You very much

[@pyotrleflegin7255]

I don't have the skills to build one, but your video was well worth the time I spent on it. Your explanation of everything in this build is quite amazing. I think I shall buy the 'next one up' ready-built - it is on offer today for just over £20!

[@ThomasGrillo]

Very cool! Amazing how you found that fault, and got it working. Enjoyed this with my breakfast. Thanks for the video.

[@markusfuller]

Thanks Thomas. this will come in handy one day im sure.

[@BonusmannTube]

Very interesting video, thanks for showing and please keep up the good work!

[@P.E.R.fishingadventures]

Thanks for the video,i learn everytime i watch !

[@SirHackaL0t.]

That knife! I see a call from down under on the horizon!

[@user-sm8wo3dj5z]

Awesome video, i like the way you explain things. I wonder if you can tell me if with one of these i can check a car alternator for bad diodes/ passing alternating current to the battery while running. Thanks!

[@rot_studios]

Great explanation on the resistor coding as well as mounting the SMD components ! I've never worked with SMD, so this was a good video to watch ;)

[@markusfuller]

Thankyou. took me a while to do those graphics while explaining the SMD codes but it was worth it.

[@rot_studios]

It certainly was

[@otiebrown9999]

Value to me as i build my own 138. Thanks!

[@Captain_Rhodes]

I made one. I like it. im sure people will scoff at the precision but for checking waveforms and quick analysis its great. also its portable!

[@demoscenes]

Really great video. I managed to assembly one as well. For me it was a very nice soft of therapy work to solder all the SMD parts. But managed :) One tip is, when you get the acrylic case, build it up a few times _without_ tighten the nuts and bolts... THAT part took me forever to get done and yep, since I had to redo that part 3 times. First time I managed to forget to pull off the plastic cover from the display :D The second time I got a tiny little protection paper from the case sitting ON one of the knobs. Heh and yeah, the acrylic case is sensitive... managed to get a tiny crack in it(not seeable) due some misalignment, from my part and yep got a bit frustrated so I gave it a bit of a bash :) Anyhow, great one as always. Happy times are above us!

[@markusfuller]

I think I will try and make a box for mine. something simple. I like the look of the acrylic case but i want something with a battery case within it.

[@demoscenes]

Yes, that would have been awesome. I am bounded to have "another" cable across the desk(as if I didn't have enough?). So yep the battery solution would be brilliant.

[@Mr.Unacceptable]

I did this a few months ago. Same model number. Works OK for basic stuff. I used solder paste and the hot air gun. The IC's I used the solder paste but used the iron to tack down one pin. I didn't have the problem you had. I wish it came in some sort of a case. I got a cheap metal case and mounted the O Scope, Capacitance/ impedance tester and Voltmeter in it. What is wrong with the Elenco XP-15K kit? The PCB burns past 8V The C2 Cap arcs and burns the board. I spread the trace apart as far as I could and got it to arc at 10V.

[@whoopjohn]

I built one and I am very happy with it, for the price. I bought it for less (yes it's an original) for £12.45 from Aliexpress. I also bought the acrylic case for about £4.50 but one piece had moved in the laser cutter and was misaligned. Fortunately it was not a critical part and I could discard it.

[@JakobHaq]

Brilliant video as usual Markus! I would love to build this myself. I've been using an Oscilloscope app so far with a Behringer UCA-202 for getting the audio in. However, I would probably get the Circuitboard with all the SMD's already on there. They're so ridiculously tiny and so is my patience. =D

[@markusfuller]

Hi Jakob. yes I should have got the one with the SMD components on it. they took me an extra hour placing those.

[@JUANKERR2000]

Mine had a faulty transistor in the negative voltage generator circuit, fairly easy to find, not too difficult to remedy.

[@slap_my_hand]

Silver Legend Thanks for not bitching around about the faulty component like some other people in this comment section.

[@JUANKERR2000]

There will inevitably be some missing/faulty components in these kits as there must be hundreds of thousands of them shipped every week. Most sellers are only too keen to remedy problems to maintain their reputation. I did not 'bitch around' as you so eloquently put it because, with the excellent manual provided, it was a simple matter to trace the fault and cheap and relatively easy to remedy it. In addition it was a quite enjoyable and educational exercise in fault-finding. Considering the cost of such a usable little DSO I have no complaint whatsoever; it is ,as you would probably say, a lot of bang for the bucks : -))

[@trainliker100]

There is an easy improvement that can be made to these (and it also applies to the smaller DSO138 "Mini" version). The waveform might look a little raggedy with high input signals. The reason is that the values in voltage divider R6, R7, and R8 are a bit too low and put a little too much load on the output of amplifier U2B. Since the divider feeds the high input impedance of the non-inverting input of U2C, you can easily raise those resistances. Just raise all of them ten times. R6 300 ohms becomes 3K. R7 180 ohms becomes 1.8K. And R8 120 ohms becomes 1.2K. Use 1% resistors. Also, I think nowadays they might all come with the SMD already mounted.

[@markusfuller]

Thankyou for that valuable information. much appreciated.

[@kingpishful]

Worth getting the case for it too

[@MegaSpeedy67]

What sort of tip for the soldering iron tip would make it slightly less of a hassle, a cone or wedge tip? thanks

[@timtrial3971]

they're even cheaper now and thank for smd resistor value explanation

[@rot_studios]

I've been needing a (portable) oscilloscope for my audio projects, but the usual ones are out of my budget. Definitely going to get this cute little thing. I only need to measure in the audible range so ;)

[@markusfuller]

there is a comment further down that says you can buy it ready built for about $5 more.

[@rot_studios]

Yup I saw it ;)

[@thevivekmathema]

i have the same, but pre-sholdered, how much max voltage input can i put on it with 1X probe. got it fully assambled original for 18 us$

[@Tocsin-Bang]

I think that it is sad that so many people can't be bothered to do something like assemble an electronics kit, it is a hugely educational thing to do. Saving a few £/$/€ is not the only reason for doing it. There is also an immense amount of satisfaction.

[@cbmsysmobile]

Bought a couple of these as they seemed cheapy and wasnt expecting them to work very well. I had a dud transistor on one which gave strange results. The diagrams on the manual do list various voltages at various test points on the diagrams, so I was able to track the fault down. I keep one indoors for odds and sods and one in the garage for car work. At £20 I'm not too bothered if it gets damaged.

[@markusfuller]

Yes they certainly are cheap enough to have one when you need it. yes I have a much higher spec scope but I think I will make a box and battery for this and keep it near the synthesisers.

[@edoardofacciotto7261]

How can I use it with a synthesizer's audio out (3,5 mm) ?

[@Spiderelectron]

The 7905 and 7805 are very static-sensitive. Could that have been the cause?

[@Mike.Nov51]

Heathkit...name from the past

[@adoniscmj3212]

Those testers never seem to test voltage regulators. I built this kit as well and it worked right away, but it started having trouble after it had been running for a while and I figured out that the 5 volt regulator was getting so hot it would burn me if I touched it, so I ordered some quality ones from Mouser and once replaced I had no other issues with it. I would say it isn't uncommon to have a bad regulator for these as they use cheap components.

[@blogtodeath4736]

Well it would have to provide the correct input voltage and magically know what voltage to expect at the output so how could it identify it?

[@amateurtech736]

If I were to do this would my reflow gun help for the smd?

[@radioham2387]

hi Marcus did you have any trouble with the 8 volt rail ?

[@Heathcliff_hensel]

Soldering SMD parts is alot easier if you have 2 soldering irons. Also if you use the tips that curve at the end it helps to position the parts without needing a tweezers.

[@neiltonks]

Heathcliff I have only been soldering for the last 6 months. I just built the music spectrum from banggood. It's all surface mounted components. Didn't seem to be that bad. Fiddly yes, tweezers a magnifying lense light and a steady hand. But pretty much did it over about 7hrs.

[@ranzee]

Hey Markus :) I've had mine sitting here for about a month to solder up (only difference was mine came with a case - which I think they've 3D printed) - and the idea to use on synths was the same :) I was going to do a youtube video of me making it - but I decided my soldering skills wouldn't make for a good comedy ;)

[@markusfuller]

I wish I had the case with mine but it looks quite funky in its barebones state.

[@mikelocejo6878]

thank you for the video. do you recomend one of these for basic synthesizer calibration and testing? i am trying to learn to repair and service my synths, but want to stay in the low budget side.

[@markusfuller]

Hello Mikel. It is a great little oscilloscope and you get a lot for the money. however its bandwidth is not very high so it will be good for most things but a bit slow for other measurements. but considering the price of this you could get a lot done with it, I believe you can also buy these ready made if you are not comfortable with all the soldering.

[@1959Berre]

What a relieve to hear a 'normal' male voice... :)

[@psemeq]

+markusfuller you can get acrylic case for it from Aliexpress ;)

[@otiebrown9999]

Excellent review! How many hours does it take to build it? Estimated. Enjoyed your trouble shooting skill !

[@markusfuller]

Hi I guess it could be done in about three hours if there was no problems. it took me longer as there was filming and drinking cups of tea etc.

[@neiltonks]

I've just bought one of these from banggood. Your not the first to experience problems with the screen . I hope mine works

[@dcashley303]

Great video as always. can you link to where you got this Markus? Would be really great to have one coming out of my mixer for all my synths etc. Do you know if there is a stereo equivalent and whether it could be powered by batteries?

[@markusfuller]

hi it was from banggood.com

[@blogtodeath4736]

www.banggood.com/search/dso138.html

[@nihonam]

I've bought one a year ago on Aliexpress. It had all SMT mounted, I just soldered through-hole. It even worked for a while, after I resoldered some obviously poor joints. And after few power-ups it just shows me blank screen with some rubbish pixels. Maybe there are more poor solderings I did. Dumped in a box for now. And sure, it's not for big engineering work, just to decorate some homebrewed synth.

[@physicsbloke9841]

I'm a Physics teacher who has stumbled upon your videos, and would you believe it I am short of oscilloscopes! I originally came to your channel for a teardown of drum machines I was interested in, but your channel is just fantastic. Really well made videos, you can see everything you want us to see. I love the videos fixing music equipment especially. I would really appreciate you going into detail about soldering components into PCB boards, with an explanation of technique for soldering. I know soldering is not a difficult thing but we all have our own ways, and I would appreciate your materials and technique. What power soldering iron you use for a PCB, what type of solder, how to clean and tin the soldering iron for beginners. It would be a video I would really value. I'm in the process of making a club at my school teaching pupils about electronics and making electronic things, so any help would be greatly appreciated.

[@Xxwolffangwarrior1xX]

Is this douable for a beginner?

[@AliensInc.]

You said "in the audio spectrum" is that only up to 20kHz? If so, this if for me not useful at all, I need something that can handle like up to 600KHz or such. Can this do this or do you know any else/better but small and "cheap" thing just like this one?

[@markusfuller]

Hi this is only up to 20Khz.

[@Neffers_UK]

I built one of these a while back, it has a fault, I'm gonna watch all of this later and see if your problem is the one you fixed, no spoilers please lol. Mine's a different fault. When trying to set it up (fixing the square wave display), the trace plummets when the required settings are selected and from memory (it's been a while) I think the signal drops low as I have to increase the scale. May be I'll have a lil tinker round with it one day.

[@Michael_Smith-Red_No.5]

I don't need one of these, but your video made me want one.

[@markusfuller]

I kinda wish it had a case but it sort of looks mad scientist as it is.

[@Michael_Smith-Red_No.5]

It really does. Crimson Tom Baker.

[@davecc0000]

+Michael Smith I get the Tom Baker ref. What's "crimson"?

[@Michael_Smith-Red_No.5]

davecc0000 Because the circuit board is red.

[@williamwinkler5497]

Michael Smith

[@mylesswanson]

So I got your dso 138 oscilloscope as shown in this link. www.amazon.com/gp/product/B0195ZIURK/ref=od_aui_detailpages00?ie=UTF8&psc=1 I got it all put together no problem. Turned it on and tested it. It worked! (phew!) Then I get to tinkering with things, testing some of its own circuitry to look at voltage wave forms and whatnot. anyways, long story short, I think I shorted it. I was testing a 9v power supply, 2000 mA (which I now realize is way more than desired). But then I think I bridged R26 and R37 (on the right side near the power supply ports) and heard the 'zzt' sound that is oh so very very bad for electronics. The screen went white. I quickly unplugged it and hooked it up to the 9v battery that I'd been using. The screen still turns on but stays white, and the "trigged" led does not respond to any input, button pushes, switches, etc. How badly did i wreck it? Are there any suggestions on how i might fix it? (like maybe I just burned out a component that can be easily replaced (oh please oh please)). Thanks in advance if you have any useful information for me!

[@markusfuller]

Hello Myles, to be honest I think that the processor or the clocking for the processor may be damaged and when you start it up the initial program will not run therefore the screen is still white waiting for data to control its pixels. if you are lucky it may have killed the power regulator U5 (78L05) which is a 5volt regulator that is very closely connected with the 2 resistors you mentioned. if you have a multimeter you can check this it should have a negative (middle pin) and a positive of about 8to9 volts then an output of 5 volts. these are reasonably cheap if it needs replacing. this is just a guess really as it may be whats stopping the processor from working. but to be honest the problem could also be elsewhere, thats leads you into lots of time faultfinding. I hope you get it running again.

[@XCILE625]

Marcus did you go to Uni to gain your expertise?

[@Symmetry77]

What kind of input connection is that? Will it take 3.5mm jacks?

[@markusfuller]

onceuponheytime Hello the input for the signal is a BNC and the input for the power is a standard power plug though not sure of the dimentions as there are so many different sizes. but basically one of those 9volt wall warts should be the right fit.

[@Penfold8]

You shoud have commented on the values of the capacitors.

[@starglider101]

Hi Markus, what is the temperature of the iron do you use to solder the SMDs? Thank you for you videos.

[@markusfuller]

Hello. Im not sure but I think the iron was set at about 280 Celcius though I was using old lead solder.

[@starglider101]

Thank you Markus, normally I use 350 Celcius, but I think it's to much for SMD.

[@markusfuller]

Im not sure what the safe limit is for SMD components. Im sure Google has the answer.

[@mr.technical1008]

Device rrecomended sir?

[@Taskuvesku]

Too bad that this DIY-product is no longer available. :/

[@ianhuxstep211]

do you know if this can be set up as a X-Y inputs

[@markusfuller]

sorry theres only the one input, you need at least 2 to get an X-Y trace.

[@tubical71]

I had lots´o´fun building mine....wrong resistor values, wrong designators...;) Of course i bought a SainSmart clone...but ever-since it runs nice and flawlessly. Let´s see what your build will turning out ;)

[@Thingsthatgopew22]

So you powered it up on a conductive antistatic mat and blame the component that shorted out on the mat? Never power up while on those mats.

[@markusfuller]

WGwireless yes but the unit has plastic standoffs in the four corners so the board is not in contact with the mat.

[@6or7breadsticks]

that is a great price for an oscope

[@ClbnaVGM]

Good job ! Mine starts..white screen

[@fritsvanzanten3573]

Nice, inspiring video. I see over here you can buy a ready one (within a case) for 45 pounds (50 euro's, large, decent company). I think for those 20-25 pounds extra (case apparrently about 7 pounds) I wouldn't take the risk. No soldering skills, but nonetheless; these tiny parts, faulty parts etc. I estimate my chances on a working device less than 5%.

[@TheOldgeezah]

Do I detect a touch of knife envy with our friend at EEVblog?

[@markusfuller]

not at all. I am a big fan of Dave Jones. but I do not know what else to use this knife for now all the dragons have been slayed.

[@snaprollinpitts]

I like your big knife, a la eev Dave

[@loocheenah]

I think you can not only attach this little thing to a synth, but to build a synth of your own... taking the best parts of the ones you've disassembled

[@markusfuller]

I keep on thinking about building another synth. the last one I built was not very good but it was nearly 30 years ago.

[@toferhomokin9598]

Ive f'ed up 2 before i had a working one.

[@SirHackaL0t.]

An esd strap! 👍👍😀😀

[@wimpevers]

Hi Markus. I think you might have accidentally bought a counterfeit DSO 138. On the DSO 138 page on the JYE tech website there is a notice about how there are a lot of fake DSO 138's on the market right now. In the notice there is a link to a forum post in which multiple people state that banggood is one of the company's selling these counterfeits. Apparently some company named SainSmart replicated the exact design and is selling them for almost half the price of the original ones. Just thought you would like to know!

[@markusfuller]

Hi I checked with JYE tech and they state that my scope is genuine. they have a run of unique serial numbers and when you register it is checked it is a genuine number and that number has not been registered before. then they tick it off so if the number comes up a second time then that is not genuine. Thats why i dont mind the serial being shown in the video as i checked and registered the night before i made the video.

[@stevewahl5041]

Logic correction: If there's a serial number collision, you know that one of the two is not genuine, but you don't know if it's the second one to register, or the first.

[@Fmacian59]

It lasted as long as an ice fish in a wiskey on the rocks. Sabina.

[@iNuchalHead]

Why is your bench covered in carpet?

[@markusfuller]

Hello . the bench in covered in carpet so I do not accidentally scratch any gear I am working on.

[@obshaky]

Had to click Like after he that package with a World of Warcraft dagger.

[@Tocsin-Bang]

Actually not a bad idea to use the flux pen before soldering SMDs.

[@Shazzkid]

Stephen Cook "not a bad idea" well its pretty much the way you're supposed to...its like saying "not a bad idea to wear a helmet when riding a bike"

[@barrymayson2492]

I make a flux from pine pitch and alcohol it came be made very thin as it drys it gets very sticky and holds the components down. The fumes are very low and it mixes ok with cored cored solder. Been doing it for a good few years and not problems so far. It clear easily with alcohol so no residue.

[@terrykelling5692]

yes I would agree, this is not a kit for the novice. those micro components would be a pain to solder.

[@markusfuller]

you can buy it with the SMD components already soldered but I think it is a couple of pounds more 9but that saves an hour of frustrating work)

[@blogtodeath4736]

@@markusfuller and also fully assembled ones too

[@karlfell3768]

Very limited functionality but what ridiculous value for money. I couldn't order a bare PCB for that price lol. Karl

[@outaspaceman]

Good grief! I can't even see surface mount components...

[@markusfuller]

believe me I was having problems. I flicked one away with the tweezers but luckily they put more SMD resistors than you need. I keep looking at the floor but as with most workrooms you cannot see the carpet let alone something 2mm in size.

[@davecc0000]

+markusfuller Required tool when working w SMDs: hoover (vacuum) w empty bag.

[@outaspaceman]

davecc0000 with a sock over the end.👍

[@Jackie-fx9kp]

太简单了吧，简直互动高中生的

[@niklaswallin9478]

Get smaller solder hehe :-)

[@slap_my_hand]

Some people buy a new car, other people buy a 10000€ Keysight DSO........

[@markusfuller]

yes my agilent/keysight cost nearly £4k with the options loaded and I only use it occasionally, but its paid for itself over the years. then I have an old analog hameg that cost me £10 second hand which I use often. you do get a lot for your £15 on this little DSO and I wished this was available in my early days as it makes a very handy tool.

[@whoisme678]

PEN KNIFE????

[@oudotcom]

hmm...so the moral from this buildup is: never buy such complex kits....only professionals like you could fix it...a such a faulty component is really bad...how much was it already assembled ?

[@markusfuller]

It was only assembled with that ONE chip. everything else I had to solder on myself. you can get a partially assembled one where all the surface mount components are already on there and you have to solder the through hole components on it.

[@Authoratah]

+markusfuller they sell a fully assembled units on ebay for about $20, about $15 unassembled.

[@markusfuller]

so now you tell me I could have saved 3 hours of work for an extra $5 ?. but that would have taken all the fun out of building it.

[@oudotcom]

markusfuller For 5 US$ more I would have rather got it assembled and tested to work...

[@Authoratah]

markusfuller Julian Lett channel got one from Banggood too and the LCD was faulty.

[@alphabeets]

You said zero- not zed! :). Are you slowly turning into an American?

[@davecc0000]

Brit "zed" = Yank "z" (the letter). "Zero" is the same on both sides of the pond.

[@TedSchoenling]

Save a life, surrender your knife.

[@MrBobWareham]

I have to ask, as you have an oscilloscope that most people would give their right arm for, why are you bothering with junk. Is it just to make a video?

[@markusfuller]

I built this small oscilliscope into a synthesizer after making the video. my big oscilloscope is for my repairs.

[@guifingers7470]

Opening mail with a big knife? Oh, come on dude, why do you try to copy eevblog? Why not think of something original?

[@markusfuller]

Im not trying to copy Dave. he uses a bowie knife I use a dragonslayer knife, the similarity is that they are both large knifes. though If I used a box cutter you could say someone else used a box cutter in a video before I did. whatever I use someone has probably done it before me. everything you do has possibly been done by someone else already. ie I teardown a mixing desk then Dave tears down a mixing desk afterwards, both video's had something for the viewer. I make a video about capacitors and people did it before I did and there will be people making similar subject videos for years to come after I did. it does not suggest copying.

[@SirHackaL0t.]

An esd strap! 👍👍😀😀

[@markusfuller]

Yes just in case. later on I attach it to my ankle because it gets in the way.