First Project - TV Oscilloscope

This was my first attempt of modifying a old TV set into an Oscilloscope. An Oscilloscope is a device that basically lets you "See" sound, it's pretty neat. An oscilloscope and a jacobs ladder (a later project) are two electrical devices essecental to any mad scientists laboratory. It's a rather simple (But Dangerous) project involving moderate soldering skills and doing a little research into how to properly discharge the electronics in order to avoid serious electric shock that could be fatal. Extreme caution should be taken any time you open any electronic device and I do not recommend attempting this project if you are inexperienced with hardware modification or repairing electronics. And if you do decide to ignore my warning and try this process for yourself I take absolutely No responsibility for any physical damage or bodily harm you cause yourself or anyone else.

The first step is to disassemble the case of the Television. I chose an older model because I liked the vintage style. This set only had 4 phillips-head screws holding it together but with a more modern set you can expect to find many more screws and they will most likely be security torx bits and many of them will be hidden. If the case does not slide open with little or no effort, DO NOT force it open, simply stop and check for any hidden screws. These are most likely hidden behind a sticker or label, some may say something like "warranty void if removed". After you get the case correctly disassembled you will see a setup very much like this one.



I'd like to take a moment to point out a few components within the TV set that earlier in this post I had mentioned that could be very dangerous and potentially deadly,

First there is the Fylback Transformer, Sometimes also know as a Flyback Capacitor



This component takes your standard 120VAC current from your wall and converts it to anywhere from 20KV to 50KV, that's 20,000 to 50,000 Volts. Think for a minute about getting shocked from a wall socket, sounds unpleasant doesn't it? now take that feeling by a factor of about 200, that's what we're dealing with here. I cannot stress enough to not attempt this if you are not completely sure of what your getting into.

Next is the Anode from the Flyback Transformer



The anode usually looks like a suction cup with a probe under it resembling a clip that holds the cap on a Christmas tree ornament, I have not removed the anode for this demonstration because I had completed this project a few weeks ago and I would have to discharge the Flyback capacitor again, and frankly, it scares the crap out of me.

And now we get to the real modification. What we are Looking for is the Vertical and Horizontal hold coils for the electron beam gun. These are usually located around the neck of the CRT and are 2 coils of copper wire wrapped around the glass of the tube as seen here.



We want to locate the Horizontal hold first, The easiest way to do this is to remove one set of wires connected to the hold and re-energize the set. When you power the set on you should see either a straight vertical or horizontal line. here is a very basic guide to help you tell which hold you have disconnected.

Vertical Line = Horizontal hold removed.

Horizontal Line = Vertical hold removed.

After Determining which hold is which you now need to determine how you want your Oscilloscope setup, There are three ways to do this, A Vertical Line, Horizontal Line or single point that moves freely across the screen. This tutorial is for a Horizontal Line setup which involves a little more effort but nothing major. Having determined which coil is which we can finally get to the soldering. For a horizontal line you'll have to discard the horizontal hold wires and move the vertical hold wires to the Horizontal hold coil. Insulate your horizontal hold wires not letting them touch each other and let them lay at the bottom of the set, we won't be needing these anymore.


Now Move the remaining wires over to the empty solder points where the horizontal wires were originally located, if you do not do this, it will not work properly. After completing this you'll need to attach 2 wires to the now empty vertical hold solder points, I used speaker wire.



Leave enough wire to reach out of the rear of the TV set and reach your input source. Now it's time again to re-energize your TV and test it out! If everything seems to be working the way you want it then it's time to put your TV set back together and put it on display.