DIY TV Oscilloscope

Scopes are expensive and hard to find locally. Here we are going to build one out of a CRT TV. THIS METHOD ONLY WORKS WITH CRT TV, NOT PLASMA, FLAT SCREEN OR LCD TV. The circuit only uses the TV Deflection coils to create a magnetic field to attract the electron beam that the gun shots. The cord you will have to cut has 4 wires + and – Horizontal and vertical coils. You will need a complementary pair of power bipolar junction transistors such as a TIP31C and TIP32C. Now here comes the hard part, being able to display a perfect wave form. You will need a triangle/sawtooth wave signal to display it correctly. There are a few ways you can do this. You can use the TV audio amplifier and a DVD ot CD with triangle/sawtooth waves on it(the problem you may come accross is distortion. Another option is to drive the H Coil with a function generator, buffered of course. You could use the TV horizontal sweep generator but then you can change the frequency.

Here’s the list of parts you need

2x NPN Power Transistors like TIP31C

2x PNP Power transistors likeTIP32C

2x RCA Female connectors with NC Switch

2x RCA Female connectors

2x Mylar capacitors(2.2uF)

2x1K resistor

1x 12VDC 2A Power supply

4x 40 ohm 5 watt resistors

4x SPDT switches

1x Pref board

2x pots 100k or higher

2x SPST Switches

24vac or less power transformer(foe a test signal)

Once I get all of the parts I will make a YouTube video.

Finding The Coils

The coils are connected to a 4-pin gray connector. Mine had red,blue,yellow and orange wires. Just cut the wires use an ohm meter to find a coil connect one coil back up to the TV and you should get a line as shown below. For example if I have a line going up and down then I have the vertical coil connected, and the 2 unhooked are horizontal.

The screens

Published by Justin Roeder

I am an electronics engineer and computer programmer that has autism. I learned by myself

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