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The Great CRT to Oscilloscope Project!

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Manticorp

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Hello, and welcome to my latest project - turning a small CRT monitor into a fully functional oscilloscope.

The monitor in question is a combined colour TV, radio and cassette player that I hope to rip the innards out of and turn into a nice oscilloscope.

Here's a pic of the device in question:

**broken link removed**

which I want to turn into something that more resembles this:

**broken link removed**

The device has quite a few inputs/outputs/controls, to name a few:

  • For Power, it can accept:
    • AC in from 110V to 240V (it has a selector on the side for selecting which)
    • DC in 12V (a rather large barrel plug which I measured to be 6.67mm in diameter)
    • A Proprietary rechargeable battery
    • A gagillion (read: 10) D cell batteries
    • A switch for going from charging the battery to operation
    • A Power switch
  • The TV part has:
    • Aerial in, selectable from the built in aerial or external.
    • Degauss button
    • V-hold (adjusts vertical scan rate I think)
    • Picture brightness (there's a screw hole next to this knob that might also adjust brightness or maybe focus??)
    • Contrast Adjustment
    • Colour Adjustment
    • A little switch that says AFC off/on which I'm not really sure what it does. Wikipedia says this is "Automatic frequency control"
  • The radio part has the following
    • Remote in (3.5mm)
    • Mic in (3.5mm)
    • Earphone out (3.5mm)
    • An XLR port labelled 'Rec/PB'
    • A switch labelled 'Beat Cut' with 3 positions, used to declick AM recordings, from what I understand.
  • And on the front panel, there's:
    • A Volume knob
    • Tone knob
    • Mixer for mic/radio ratio
    • Switch between casette, radio and tv mode
    • TV tuning with switch between UHF, VHF L and VHF H
    • Radio tuning with switch between MW, LW and FM
  • There's also a small light switch and a counter for the tape player, which has it's own usual play/stop/record controls

I've managed to get my arduino to output stuff to the little screen using the great TVTuner library and hooking the arduino up to the Aerial, so at least we know it works:

**broken link removed**

Because all analogue TV has been switched off here, I wasn't able to test it otherwise (and I don't have an old VHS player or anything handy!)

I'm going to try and follow this great instructables post where he transformed a regular television into something quite similar.

Improvements I hope to make to this would be to calibrate it vertically to get accurate voltage readings and to be able to adjust the timebase accurately, so maybe instead of having the flyback transformer driving the horizontal frequency, using a different circuit.

It would also be great to switch from magnetic deflection to electrostatic deflection to be able to measure higher frequencies, although this is a big ask.

Any help and advice would be much appreciated, I don't have much experience working with these high voltage/frequency circuits!

Stay tuned for updates though!

Here's some more pics of the item:

**broken link removed****broken link removed****broken link removed**

H
 
Any help and advice would be much appreciated

At the risk of appearing to be a completely negative old sod...

... Don't bother, don't waste your time.

Been there and done that about 50 years ago.

Yes you will be able to make some squiggly lines on the screen and I am sure that you will learn something along the journey from obsolete TV to squiggly line display thingy.

But oscilloscope? No, I do not think so!

JimB

Rant_Mode=on;
Why does the Instructables site publish such dire rubbish!
A few weeks ago there was someone here on ETO asking about building a transformer for some obscure modification to an audio amplifier, the transformer was something from Instructables using an old steel bolt for the core.
Rant_Mode=off;
 
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I'd love to - but it's a bit of a long way to go .

Just do all my wifes silly projects that keep taking time away from the important stuff I need to get done and I may consider giving up my 100 MHz digital unit!

Seriously I love her but half of my construction delays in this project start and end with her. :(
 
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Manticore, on this thread the members exposed with more detail why a TV oscilloscope is such a bad idea
https://www.electro-tech-online.com/threads/tv-pc-as-oscilloscope.111307/


Just do all my wifes silly projects that keep taking time away from the important stuff I need to get done and I may consider giving up my 100 MHz digital unit! (

What kind of projects? At least she asks your help with her projects, instead of using you as a human cloth hanger on the mall :D
 
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i sincerely apologise for this question im about to ask but im increadibly tired.. i tried to make my own post about an o-scope problem i'm having and cant seem to find where or how to do it.. any input is appreciated.
 
Hello IMetMattHoopes!

You will have more luck creating your own thread

Go to home (electro-tech-online.com)

Click on Forums

Pick the category that better fits your problem (general electronics chat, electronic projects design, electronics repair)

click on the blue button create new thread (it's just above the thread list)

and it's done :)
 
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