Make an oscilloscope out of an old Crt computer monitor!

This is my failed entry for the dead computer contest. It is an oscilloscope that is made out of a broken computer monitor and run by a dead computer. Now if you're like me you have an old monitor that only 2 of the 3 colors work. (Red and yellow.) I will show you how to take that monitor and make it into a fully functional oscilloscope. A lot of credit  goes to the 4th doctor and this Instructable. Plus the hundreds of comments on, 'can I do this with a Crt computer monitor?'

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 Now how this works is the image is provided by a semi-dead computer. My computer can only display the win 98 screen but that will work for this Instructable.The line is really just the win 98 load screen just compressed into a long line. This will work with any computer that can display something. The monitor also does not have to be broken, but to comply with the dead computer contest rules, mine is. This oscilloscope is FULLY functional, not just a visual toy. So please treat this oscilloscope like an oscilloscope or else could result in electric shock.

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  Now the fly back transformer in this thing is running at 30,000 plus volts. So be safe and don't hurt yourself. Electrocution from this thing can result in serious injury or death. If you have any wear rubber shoes and only work on this project with one hand. Why? You ask. Because if you use two hands electricity could jump across both arms and hit the heart on the way. So only use one hand. And also if possible wear rubber shoes.

Step 1 Materials!

Things you will have to have-

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• wires
• Crt monitor
• dead computer (as long as it can display something)
• soldering iron and solder
• wire cutter
• screwdriver
• electrical tape
• Speakers with built in amp or an amplifier and speakers

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The fly back transformer in this thing is running at 30,000 volts so wear rubber shoes and do not touch two parts of it at once because the voltage can arc across your arms and heart if you do so.
BE SAFE

I am not responsible with what happens to you in the process of dealing with high voltage,
so don't shock yourself in the first place!

Comments

[TheRealPeregrinus]

Instead of an old PC can anyone recommend a small circuit that could be connected to the video cable to just create a white screen? Would +5vdc on pins 1,2 and 3 with pin 10 as ground work or are more complicated signals needed?

[ryn0909]

Overall your instructions were good, but they could use more detail...... having said that.......... Good Instructable. I just finished and it works great. nice thin blue verticle line, unless i put it on its side. lol Ive only tried it with injecting amplified music into it and it works great. i intend on using it to check circuts on a broken lcd tv that im tryin to fix. thank you for the good work and effort.

[ukkr]

i have no idea

[jaxxster1]

will the crt moniter still run after this mod is used?

[IW5 Industries]

If you reconect the wires back to the circuit board.

[emerson.john]

If your CRT has >30KV at the anode it is generating X-Rays and has probably sterilized you by now. Which maybe is not such a bad thing.

Actually, the monitor has a HV protection circuit, so it will shut down before it produces 30KV.

If you want it to run horizontally, why not just rotate the yoke 90 degrees?

[IW5 Industries]

thank you

[stompythefish]

Why doesnt it work the other way (hooking up the vertical sweep to the audio signal and allowing a horizontal line to translate the waveform) turning the monitor sideways would really annoy me.

[frollard]

The vsync runs at whatever framerate you put out- usually in the 60hz range.  The hsync runs in the kilohertz - as the screen scans lines horizontally, one at a time.  You get far greater resolution in the original horizontal axis.

[IW5 Industries]

Im not exactly sure but i think it's because the horizontal sweep has a slower sweep rate then the vertical. but it could also be the other way around.

[nicknewbie]

when you switch them the CRT tube will whine but theirs usually a pot on the board for tuning it you just sweep both directions until the whine stops it works for tvs idk about monitors though

[IW5 Industries]

monitors and tv's are a completely different species of crt. trust me. Iv'e made oscilloscopes out of both

[nicknewbie]

if you swap the x and y axis wire you will get the horizontal line instead of vertical

[IW5 Industries]

like i have said many times before, when you do that, it hinders it's use as a true oscilloscope and does not measure waveforms propery it only creates an expanding box

[mspearin]

when i cut te red and blue wires and i turn on the moniter i get a high picth noise. Is there anyway to fix this?

[25kv]

u messed with the the wrong whires of the VGA connector of the monitor and its just the CRT just find how mutch bits it is and l@@k for a chart of witch whire goes where

[IW5 Industries]

Hmmm, I have no idea. mine starts to sqeal when it overheats, so maybe your monitor is overheating too fast.

[DemonicRoss]

 I'm not sure if this works but i remember hearing that if you cut the y axis wires and connect them to the x deflector that it will run horizontally.
It's been a while since i heard this so i may be mistaken and it was for a tv not a computer monitor which i'm not sure that makes a difference.

[25kv]

it does because a TV has a coax or A\V inputs and a monitor has aVGA or some have a VGA and a DVI input (blue VGA white DVI)

[IW5 Industries]

It doesn't. It just creates an expanding line instead of an oscilliscope.

[LeviMan_2001]

Alright so help me out here. I cant seem to find the horizontal wires! I've got a few wires that go to the board that sits on top of the coils. There's a pair of brown and yellow wires, and no matter which one of those you disconnect, it's just like you disconnected the vertical (and I think that's what it is). Then theres a plug with two big blue wires and two big red wires. Those wires give big AC power to the little board on top (and no matter which ones you disconnect it either stays the same or the image disappears) Then there's a pair of small blue and red wires these if you unplug them just make the screen go black. This is annoying! Maybe I'll just have to salvage what I can from this (FLYBACK!!) and forget about the O-scope.

[25kv]

its just the VGA but you need to find out how mutch bits the monitor is and l@@k online for a VGA chart

[IW5 Industries]

to me it sounds like the red and blue wires that make the screen go blank are the ones you want. either you have a very old crt, a very new one, or one ive never seen. what brand is it?

[LeviMan_2001]

It's from '98 and it's a hitachi. Oh and the small blue and red ones, I got confused, those don't do anything when you unplug them, or send audio through them.

[IW5 Industries]

hmmmm.... thats the same year as mine. Could you send a picture of the insides?

[johnybody]

Okay, so ...

i think I have exactly the same bunch of wires as you . 4 wires that come from the circuit board and connect of a small circuit on the deflector.. ( theres a blue, red, yellow and brown). When I cut the red and blue, then I injected some music. But now my crt monitor doesnt go on! ??! When I reconnect them like it was originaly, my monitor work well.

Did you experienced this problem?? What can I do?

[IW5 Industries]

are you sure you connected audio to the wires going into the deflector coil, not the circuit board? this coul cause that problem to arise.

[johnybody]

Ive tried it back and the same result happened...: :(

Is the input mono? Ive tried to put the + of the music signal on the red wire and the ground on the blue one. I have also tried the opposite....the crt monitor always shutdown byitself 2 secondes after i press the power button...

[25kv]

i just bet the video card is dead or the ITE connector but u know that it could be the VGA

[25kv]

the CRT of the monitor might get screwed up because its sideways ans then it might not give u a good reading it can curve and bow and stuff like that
and also because that you can messup w\ the VGA so it will give u a bad reading but i'm not saying this is bad thoe.

[25kv]

cool i need that and a lot of people know me and the give me junk like this

[spel3o]

haha, when I made one of these tool was the first band I played on it too, funny coincidence

[Dannne11]

and the clicking just go faster for every secound.
i think i might tok the x axis or some thing.
are duct tape Energized?

[Dannne11]

when i start the monitor it sound like click click click so is that normal or what??

[matver01695]

I have conneced the wires properly but it only works for 30 seconds like I said before.

[matver01695]

when I do the project my ampifier breaks down after 30 seconds and now it's unusable, does anyone know what is doing that?

[stormsirens2]

 I have an old CRT monitor I took a part, but, darn I'm not sure if I messed it circuitry, oops, I remember I bent the pins on the tube and took the plastic that holds the pins together, shoot. but as soon as I get a working one I'M DOING THIS :)

[technoguy94]

Could you give me an overview of what I need to do to the monitor? Its not really clear...

[IW5 Industries]

sigh... you cut the red and blue coming out of the crt wires and connect them to the speaker. close it up and your good to go.

[mspearin]

When do you plug the monitor into the old computer??
do you need to have the monitor plug into a computer or is there a way to get it so you dont have to have a computer to use it???