Diy oscilloscope

Posted: 7/8/2008 7:15:12 PM
Spooky Ether

From: Nashvile TN

Joined: 9/9/2007

I saw where you can make an oscilloscope out of an old black and white tv . I do not know a lot about electronics but this looked easy and it was when I got done I played my Theremin thought the scope looks very cool! The web sight is I sugest doing this if you can. If any one knows of mods to add to the tv/scope post them. thanks
Posted: 7/9/2008 12:54:31 PM

From: Escondido, CA

Joined: 2/6/2008

There's lots of freebie software to make your computer work as an oscilloscope. Check out

(sorry for the slightly long URL)

I suspect people are going to find all sorts of silly uses for their TVs after 2009 when the FCC shuts of standard broadcast and "downgrades" to HDTV. "Make a theremin from your old color TV ..." :)

Personally a bit of snow on a weaker channel is a whole lot easier to watch than half the picture "pixelating" because the decoder got lost!


Posted: 7/9/2008 9:20:21 PM

From: Atlanta, Georgia

Joined: 4/24/2008

By way of cautionary note, this:

> old black and white tv

and this:

> I do not know a lot about electronics

are usually not a good combination. Cathode ray tubes and their high voltage supplies are nothing to be trifled with if you're not really sure of what you're doing. There are much better projects for beginners!
Posted: 7/9/2008 10:06:15 PM

From: Connecticut

Joined: 10/10/2007

I second that matt.britt
Posted: 7/9/2008 11:01:12 PM

From: Richmond Hill, Georgia

Joined: 9/18/2005

Television CRTs have in excess of 15 KV on their anodes, plus there is the danger of implosion should you fracture the picture tube.

Unless you know absolutely what you are doing, I would strongly advise you to leave this project alone.

We have very few thereminists in this world. We don't want to lose you.

Be safe.

Philip Neidlinger
Richmond Hill, GA
Posted: 7/19/2008 3:26:18 PM

From: Eastleigh, Hampshire, U.K. ................................... Fred Mundell. ................................... Electronics Engineer. (Primarily Analogue) .. CV Synths 1974-1980 .. Theremin developer 2007 to present .. soon to be Developing / Trading as . ...................................

Joined: 12/7/2007

Using an old CRT television is (unless you absolutely know what you are doing) both dangerous and pointless.

TV's use magnetic deflection, CRT's in oscilloscopes use electrostatic deflection - magnetic deflection is too slow for direct use in any reasonable 'scope.. so any idea about getting inside a TV and messing with the deflection circuits to directly drive X from a timebase and Y from an amplifier is a waste of time (I know this from bitter expierience trying to make a 'scope this way when I was a teen)

This leaves the option of digitising the signal, storing it, and replaying it at line rate (15.625kHz if I remember correctly) synced to the frame frequency - you need to build a full digital TV output stage generating sync pulses etc, and 'drawing' the waveform.. I did exactly this for Lord Medical Ltd (The company Jeremy Lord Synthesisers became when the synth market collapsed) back in the early '80's and this was fine for 'chart recorder' replacement displaying ECG's etc - but was limited to about 1kHz max.. This design had a large board full of TTL and memory, and was not a cheap or easy project.

Today we have PC's and all the hardware and memory (undreamed of power, back in the 80's) is sitting on your desk - Your sound card is a perfect A to D for implementing a 'scope for use at audio frequencies.. Software to turn your PC into a 'scope is readily available.. If you need a real scope, 20MHz 2nd hand analogues are available cheaply..

It is a catch 22 - You need a scope to learn electronics, and until you have learned electronics 'hands on' using a scope, you are not in a position to try making your own!

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