Oscilloscopes are a great tool to have on hand for troubleshooting electronics, but what happens if it breaks and there’s no spare to be found? As strange as it may sound, some people still have CRT TVs stored away in attics or garages, and with a little reengineering, they can be repurposed as an analog oscilloscope. Walden from NerdLabs has found a novel way of transforming an old TV using a simple process of connected a few wires, but it should be noted that messing around with those retro CRTs can be dangerous, as they can still hold a sizable charge, even if unplugged.
Turning a TV into a o-scope isn’t a difficult task and requires the utilization of four wires that control the motion on the screen, and by inputting a signal through those wires, it can be used as a troubleshooting device. The process involves opening the rear panel on the TV, prying off the suction cup off of the back of the CRT, and separating the wires that provide continuity. These wires are responsible for vertical and horizontal control. The output is connected to an audio amplifier with an audio cable, while the amplifier input acts as the o-scope device.
Walden connected a headphone jack to the amplifier’s input, then played music through the circuit, which could then be seen as a waveform on the CRT. He states users can attach a 10-1 or 100-1 probe to lower the input voltage, allowing them to use the DIY o-scope to troubleshoot electronics projects. Walden has uploaded a detailed walkthrough of his TV oscilloscope on his Instructables project page for those who would like to recreate his build.