HACKED!: CRT TV becomes a crude Oscilloscope
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- Опубликовано: 25 мар 2017
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In this episode of HACKED! I will show you how I converted an old CRT TV into a crude Oscilloscope. During this process I will talk about how a CRT TV actually works and how we can utilize the deflection coils of it in order to create our own picture on the screen.
Music:
2011 Lookalike by Bartlebeats
Ecstatic Wave, Jens Kiilstofte
machinimasound.com/music 
Наука
WARNING: You have to discharge the CRT because it acts as a capacitor and can deliver 30-40kV. Please do this only if you have knowledge of CRT's and the voltages that a CRT uses. Old B&W TV's use around 15kV.
I even had a dead small B&W TV and after about one hour of testing it still had a charge. Also never discharge it with a screwdriver because you can damage the CRT and there are many dangerous materials on and in a CRT, and if you do it, do it outside and wear a facemask, and really do that if you vent it, otherwise phosphor can be blown of the screen (mercury too) and that can definitively cause bad lung damage, that was with the same B&W TV.
Definitely. NEVER put your fingers behind the rubber HV cup fixed to the tube - I once did this on the back of an old colour TV more than a day after it had last been powered, forgetting that the inside coating of the tube would still be holding a charge. The force sent me flying across the room and I guess I was lucky not to have been killed.
That's just theoretically, forget what you study, I always work with this kind of stuff and there is no problem, the only dangerous parts are the big capacitor but not a thing to kill and the THT output, nothing else
You're more than welcome to make a video proving what you said :)
Can't agree more. The only time I took apart an old CRT, I made sure I took all the safety precautions and discharged he CRT. The spark is surprisingly large, and could definitely be a lethal shock. Stay safe out there!
There is "only" 25Kv on this modern color CRT.
Back in the early 70's I worked on TV's. I disconnected the horizontal and vertical yolk connections and wired them to the left and right channel outputs of a stereo amplifier. It presented a fascinating Lissajous pattern of the music.
I just remembered that I left the original yoke connected but set to one side. Then I slipped another yoke onto the CRT that was connected to a stereo. Important to the HV to keep a load on the horizontal output.
Henry Pitts When I made this test on a 1969 color TV, which still used vacuum tube to drive the horizontal/high voltage (+25kvolt), it appeared to work well with horizontal yoke unplugged. in case of overload, such as short circuiting the high voltage, the tube plates were glowing red but survived. With fully transistorized TV, any small stress and the high voltage transistor is destroyed. Not really friendly to curious experimenters.
@@Henpitts You must have done the _exact same thing_ that my highschool electronics teacher did! ;)
Can you help me do that with an old mega watchman TV please Henry?
Lissajous pattern? The logo of the Australian Broadcasting Corporation.
Back in the age of television when I was an awkward nerd, the late 1980s, a fellow nerd told me that connecting the deflection coils to an audio amplifier would create trippy patterns. Really just that, the deflection coils where the speakers to the amp. Classical music was mesmerizing. Waveforms seemed to rotate in 3D as the sound decayed. Before you do any of this, know a CRT can KILL YOU!! Yes, discharge the kill you capacitor, which is the big old CRT tube itself, by shoring chassis ground to the connector under the suction cup thing on the tube, the high voltage connector to the flyback transformer. If what I just said was Greek to you, never open a CRT case, high danger.
So did you connect the CRT deflection coils X and Y axis to the Left and Right channels of an audio amplifier? As i just wanted to know if that was how you sort of got a 3D affect on the CRT display.
@@ewansbuzz127 Yes, left and right to X and Y. To an old school transistor and heavy transformer amp. As a note decays subtle changes to the frequency takes place, and the left and right are out of phase, resulting in what appears to be a rotating loop or infinity sign. Best to find an actual oscilloscope to observe the phenomenon.
Your handwriting is soo satisfying
Superportvein neater than most native English speakers huh
Superportvein he is also left handed, which adds surprise.
Ozzeip Piezzo really? you learn something new every day I guess. thanks
A lot of native speakers learn to write when they are like 4 years old, and then never attempt to improve it :P This is true for a lot more languages than english.
ikr, thats the power of a gel pen
In 1990, at University, we heard about students who had successfully driven an oscilloscope to act like a CRT TV with the X, Y and Z inputs. Z input was used to alter the brightness of the trace.
They were able to watch the World Cup matches on a tiny screen even though they had no access to a television.
That’s what I’d love to see!
ruclips.net/video/5FYF5uhCzAM/видео.html
Using an oscilloscope to make an oscilloscope
Thanks for over 300 likes! I appreciate that!
Thinking quickly, Dave constructs a homemade megaphone using only some string, a squirrel and a megaphone
it is the same: "using gears to make more gears"
Well not really
He used a function generator
*sOuNeeDaNoScIlOsCOpEtoMaKeAnOsCiLloScOpE cLiCkBaiT!!!*
(and yes, i know, it was a function generator and not an oscilloscope)
Oscilloception
This is way over my head when it comes to electronics, but I still love to watch it..
"People who have too much time on weekends and so they just refresh their youtube subsciptions every few minutes" -squad
there is a thing called notification
"People with too much time"
Damn I wish I had even enough time to study
K1ngjulien_ people with no life 😂
don't you think that you have no time for you own interest because you are working on somebody else. somebody else like the one who created experiments like this.. before there where business and jobs there are people who do the testing and invent things for their own satisfaction not for money.
K1ngjulien_ me
Instead of oscilloscope, you can do an audio visualizzer, showing you the audio wave of your audio output device (like mp3 player)
Marek S that sounds awesome and would probably be more interesting for most of us
You could do this also on an oscilloscope. Nothing changed. And also mentioned and Scott replied.
I think they mean a spectrum analyser, maybe? Like you get on EQs?
As he stated, it couldn't be used to perform any accurate representation as the crt was not tuned to perform this function.
This is a good idea. CRT give much better view of the music than a few LED
Using a color CRT, I suggest the following:
1 - disconnect the horizontal, but replace it by an equivalent inductance. Most TV require a continuity on the horizontal deflector as protection for the CRT. The high voltage fall to low level if the horizontal is disconnected
2 - connect the horizontal to a 6 volt transformer. We want a 50 Hz or 60 Hz sinusoidal wave, not the saw tooth wave shape of a typical scope
3 - disconnect the vertical deflector, connect it to your audio output of an amplifier. The impedance is around 8 ohm to 16 ohm, similar to a speaker
4 - disconnect the 3 wires that control the red, green and blue of the CRT that comes from the main board going to the PCB on the rear of the CRT. Apply 3 volt DC. This allow the beam to be constantly ON instead of flickering with the video data. You may still get an annoying black portion which is the retrace blanking. This can be removed by increasing the total brightness, a voltage control located on the high voltage flyback. If there is potentiometers on the PCB on the rear CRT, increase these as well to eliminate the retrace
5 - Use a magnet (from hard drive or micro wave or speaker) near the read of the CRT to separate the 3 colors. Modern CRT have such excellent convergence that the lines would be just a boring white. Move around the magnet until you find a location where each color separate, while avoiding to mix the color. You want the 3 saturated red, green and blue, not a mixed half ass of yellow, purple all jumbled.
6 - You may want to swap the horizontal/vertical since the horizontal can be swept 300 times faster. In that case, rotate the deflection coil by 90 degrees.
This modification of a color CRT display music in a really majestic way. When the music contains lot of bass at 50/60 Hz or any higher multiple, very nice lissajous shape appear. The 3 colors are much more interesting to look at, compared to the boring green of a typical scope.
If you own a function generator (as you mention in the video), replacing the AC transformer by the output of the generator, going thru an audio amplifier, you can set the scan frequency to the dominant frequency of the bass for each music you play, allowing these lissajou figure to appear. A further improvment would be to use a phase locked loop to detect the bass frequency on the fly. Displaying the locked frequency would complete the design for a tool that reveal the musical note for each base tone.
i love how the concepts were explaines... including the effects of voltage drops, deflections of electrons... Good job Mr. Scott!!!
i really like small crt's.. they have something special.
Gijs gotta love that high frequency sound. Mmmmm
look up DH3-91
Gijs I have the same feeling
I wish there is a speaker to salvage in the that tv...
they normally have a sharper picture, which leads me to think something was wrong with the one in the video, appeared to be out of focus which is usually not a good sign (symptoms of a weak crt), maybe it can be adjusted.
This kind of project was one of the very first I did a very long time ago, when valves were still in use. I got a very large oscilloscope which interestingly was also pretty precise and allowed to see signals which normal oscilloscopes were not able to view, due to the inferior resolution.
You NEVER seize to impress me Mr.Scott. Well done and thank you for these videos!
Ha, so cool - I did this too - many, many years ago. Very useful to check rectifiers, and as a music visualizer. I went much more low tech and simply connected the secondary winding of a small mains connected 50Hz transformer to the horizontal winding. Your usage of a stereo amplifier to boost/impedance-match both deflection coils is quite brilliant. Thanks for posting.
amateur radio engineers were doing this 35 years ago with big old 22" tv's, I remember seeing one that an engineer had made
Damn that sounds cool, I want to see one of these modified units
Awesome Video! Love your work!
great work great Scott
He realllyy poses great knowledge of electrical engineering
Good going
I think this is one of your best DIY video!! Kudos!!!
Cool experiment! I enjoy this type of video. It was thoughtful of you to also share the moments you got it wrong. I learn so much from those moments. Thanks!
it's really enjoyable watching you draw the schematics, and your handwriting is beautiful.
I frickin love this video, I've been thinking of such a thing. You literally put my idea in head into motion. Thanks Sir!
Love u Scott you really are great
great project as always, Sir!
on a store-room shelf is an old CRT monitor being saved just to play with. now with your guidance
i feel ready enough to dive in and have some fun. i'm one of the few left of a shrinking population who
grew up with CRT TV's... back when grocery stores had vacuum tube-testers and spare tubes for sale.
In terms of creativity in think you've excelled yourself here GreatScott - Well Done! There must be some more useful things that can be done with all the CRT's laying in landfill all over the world!?
Very Interesting Demonstration.
We all know that this will never be a useful instrument-
but, as fun and clever demonstration- It works.
Well Done.
You're so smart. I love watching your channel. keep up the great work, greatscott. ill keep watching.
Thanks, I will try to keep it up.
Congratulations, beautiful work, I'm also building one ... Greetings from Brazil!
Cool, if you want, you can also check out my version on my channel :)
your TV oscilloscope is the best on the entire internet! Congratulations!!!
great job greatscott
Good work... Keep going
Thank you so much for this! I was trying to figure out how to make a trigger circuit for a DIY CRO for some time.
You are a mad man!!! I wouldn't even know where to begin on a project like this.
You are such a genius. Stay creative!
Hey Scott! You are truly great...
I didn't understand anything, but I love to watch these anyways! This channel should be bigger, I bet one of my teacher would love to see this.
great presentation -- thanks -- I did this to old TVs in the 1970s.
Feeling nostalgic.. glad to see this 👌
Impressed as always!!
this was awesome, thanks for sharing.
Man you awesome!I wait for your videos.
thanks Scotty, some useful info in this vid
I've learned some things about CRT's. Thanks! :) .
Interesting. Keep up the good work.
Nicely done. I was a expected it to be one of those little black and white sets.
3:24 I don’t want to here you say that ever again, my friend. You’re helping others understand a lot of things. Keep up the good work.
Thank You,Scott,for Your videos!
"scoot"
craftxbox Aha
U Liked Your own comment?
i didnt?
craftxbox "i" Oh,that grammar...
wow, impressive work!
I remember my Grade 11 highschool electronics teacher showing us his version of this hack; he actually used two separate deflection-yokes, one on the neck of the tube, and the other off.
The class was blown away when he applied an audio signal, and got multicoloured, psychedelic Lissajous patterns on the screen, that varied according to the rhythm of the song he was playing. *VERY COOL!* :)
Damn neat handwriting and freehand diagrams!
I'm actually amazed this worked. Normally the horizontal windings of the yoke are part of the HV circuit of the flyback transformer which generates the HV for the CRT anode. On many sets, if you disconnect the yoke you won't get enough HV to light the CRT (unless you substitute the horizontal coils of the yoke with a suitable inductor connected to the flyback).
i dont have any idea what he's talking... but still .. im watching it till the end... awesoomeee..
You are really GREAT man!! .. I've learned a lot from you !! Thank you so much, keep up the great work.... i wish i could support you on Patreon :(
I HAVE BEEN WAITING FOR THIS!!!!! 😝😝😂😂😂
I did a mod like this years ago with an old black and white tv, I utilized both the x and y coils to create Lissajous patterns by amplifying the signals from the left and right channels of a record player.
This is a great video.. As someone trying to make a hobby of fixing old arcade machines, this takes a little of the mystery away from the CRTs I'm afraid I'm going to electrocute myself with! :-)
Love this hack. Still haven't done it. But it's been on my list for years. Gonna do it.
So great idea! So great video!
Thx
an even technical rather than a simple setup.
Cool nice Awesome.
awesome. keep up the good content
I did this to look at distortion signals from my guitar pedals design. It works just fine and its perfect for the job
you are a boss man. I hope to learn a lot from you
I had an old Tektronix 2465 oscilliscope that used to belong to my dad. That thing was ancient, didn't have nearly the functions that today's scopes have, weighed a ton, but was approximately 1,074 times cooler than any other scope I've ever seen, just because of how old it was. I ended up giving it back to my dad before I moved.
I used to make and sold some of these in the mid 1970s when I was a child, but I used to rotate the coil. 90deg, I also added an isolation transformer to the input, this was also for impedance matching. I bought small used transformers from Henry's radio in Edgware Road in London. There were a lot of abandoned TV sets at the time, probably because they were VHF only, and broadcasts for the new BBC2 channel was only on UHF.
Very interesting.
Was thinking about turning one of these small TVs into a clock using an oscilloscope clock board, but that would require a lot of work as the yoke would have to be rewound.
Great idea, I may actually build this with the old black-and-white CRT I got a while back.
Some improvements that I may end up making:
-The arduino has an analog comparator built into it across AIN0 and AIN1, this can be used to enable a more sensitive trigger than with just software analogRead()
-I'll probably try using the arduino's high-frequency PWM directly for the timebase output with a filtering capacitor. I've used it successfully before for playing PWM audio samples, and it should be good enough for a basic timebase.
Man that was brilliant! as crude as it was very cool
Love your videos but also your diagram drawing skills! :) Make a video some day about your technical drawing tips.
oh sweet you have All in One Tester :)
Hehe, used to do this with old monochrome monitors.
Tip: use the horizontal deflection coil and leave the vertical coil connected to the display. Loosen the screw which holds the clamp, which holds the yoke (the assembly which the coils are wrapped around) onto the tube, and rotate the entire yoke assembly 90 degrees, so that horizontal is now vertical.
Sir, this cool stuff and your explanation has inspired me. I wish you could be my mentor.
Muy buen experimento me encanto!! Excelente.
Man ... U really great
nice finally a use for my portable crt tv
Done that in my early days in the 1980s. Good for a cheap cro but limited in bandwidth and you do get distortions from the deflection coils. Always best to try this with a B+W TV.
Back in my university days I took an old TV and hooked it up to my audio stereo equipment so that I could have a fun music display. It didn't really matter if it was triggered correctly. I was just cool to look at!
Great video thanks
Great scott you ate genius
I need to find one of these kinds of nerds during the apocalypse and guard him while he/she teaches me their secrets.
great video.....thankx
wait, if you use both x and y with a stereo audio source, will that make a vector-scope
nice work
great project!
AWESOME PROJECT !
Oh My God! such a genius!
Creative person who are left handed. Thumbs up.
How do you always manage to post something every week and be on schedule? You also have a job and you're studying for your master's degree (I think), so you must have a very busy schedule. Anyway, I love your videos :D
Making video is my job. But doing a masters degree along the way is quite stressful.
GreatScott! Master degree in what field?
Joseph Nicholas he may answer but RUclipsrs typically get a dollar or two per thousand views but the CPM value they call it varies a bit I think. So 100k views is something like a hundred or two hundred dollars seems he gets about 200k views on average so about $400 per video/week or $1600 a month, so not a ton but good income for a student part time thing.
Shaun Husain Plus the Patreon thing, if I were right, it's 1000$ on 27th March.
Counting the views from the 'before' video, I'll say it's about 3000$ per month, which is awesome btw.
But with that degree of his, he should be producing about 6K per month. I hope more patrons are coming.
Thankyiu i greatly need that
Should it also be possible to make a phase-scope out of this?
Superb! I like the melding of analogue to digital devices. Maybe a high voltage warning at some point in the video , I suggest the beginning.
Your channel is the best on You Tube for this stuff - excellent work and format! How about adding a Freeview tuner module to a non Freeview LCD TV? Make many cheap semi-obsolete TVs worth buying then...?
makes a nice background decoration
this is some advanced stuff :O
From Great Scott, I learnt that, knowing to use osiloscope well , signal generator and ardunio, a person could do anything he - she wants!
could you make soldering station with display?
It is on my to do list
With PID control ok :D
But for people, like me, who have ordinary soldering iron... So we can build it ourselves.
It's not fun that way to me because I love electronics and want to learn as much as I can
A good soldering iron can make you look like a pro (trust me, I have very little skill). The other big thing is to use Lead-based solder (I know, cancer, instant death, etc... Only do that outside), so its not recommended. The best is obviously the soldering iron. I started with some cheap 30w soldering iron, and it took forever and it looked terrible. Even spending about $5 on a 60w helped, but it does get too hot so you need to unplug it every couple minutes for about 10 seconds. My favorite one is a temperature regulated 200w soldering iron. I can set it to 200c thorough 480c and it auto-regulates itself to that temperature. Plus when you need to solder some big wires, it has plenty of power. Unfortunately it runs off of 220v, so I can't just plug it into a normal socket in the US (actually it had UK 50 Hz plugs on it, but it seems to do just fine at 60 Hz). Its great for tiny precise wires where you don't want to burn a PCB like I used to do all the time, and I mostly got it for soldering solar panels because I kept breaking them with a bulky soldergun and it takes a lot of heat to get wires to stick to them. As far as time saved, that was about 10 hours on just that 1 project, its really easy and fast now. I think i spent $20 on that iron, and it was well worth it.
good job!!!
Thank you.
I grew up in the 90s, so DEFINITELY had CRTs, but I just don't remember scanlines on any of the CRTs we owned. Yours seemed to display the similar "honeycomb" pattern my tvs had. Maybe since we bought quality tvs back in the day, they weren't horizontally arranged. I don't know. I just don't remember scanlines growing up. The closest I can think of having it, was the GIANT Mitsubishi we had in the basement, but pretty sure that was a rear projection tv and not CRT. Given its massive size. And the scanlines were induced by the corrugated front plastic.
Only now one realizes how much work went into designing and building real scopes.
Great try to great Germany. ..Thank u sir