Evan Monsma Turns a Broadcast Camera Viewfinder Into a Sharp Little Standalone TV

Evan Monsma started with a viewfinder built for a professional broadcast camera. Inside sat a small monochrome CRT, the kind camera operators once relied on for precise framing during live shoots. He wanted that same screen to work on its own, showing ordinary video signals without the rest of the camera attached.

The original equipment came with an eight-pin connection that not only provided power but also transported video and control signals back and forth between the viewfinder and camera body. There wasn’t a publicly available pinout, so Monsma decided to get his hands dirty and open it up to see what was inside. He used a multimeter to map out each and every wire, and voilà! He discovered that a yellow conductor supplied around 12 volts of power, the black and red wires served as ground, and the video signal was transmitted via a grey line, and it turned out that just three connections were sufficient to operate the tube.

He cut the factory wire and built a simple adapter, allowing the viewfinder to be powered by a wall power supply or a suitable battery via a regular DC barrel socket. He also installed an RCA jack to accept composite video; both connectors are now mounted on the rear of the enclosure, securely fastened using sticky adhesive and heat-shrink tubing to prevent them from coming away during regular operation. He cleaned up the old harness by attaching heat-shrink coverings to the unwanted wires and storing them out of sight.

The focus-peaking switch still works flawlessly, and you can adjust the brightness and contrast to achieve the ideal image. Monsmas also tested the side panel using an HDMI-to-composite converter and was pleased to note that even with the contrast turned down, text remained visible, and the dark part of the movie had more information than you’d see on many laptops under similar settings.

A wooden base is what gives the finished piece its proper shape. Monsma carved several channels into scrap wood to hide the cables underneath, painted the screw locations, and then secured the metal viewfinder body to the board with little machine screws. A application of Danish oil on the base and a fresh coat of white paint on the housing transformed it from a Frankenstein’s monster to something that looked like it belonged there.

The original sunshade now flips over to provide a flat surface on top of which you can place another small gadget. You can have the viewfinder up and running in seconds; when the tube warms up, the image appears and remains solid. Monsma ran games via it and watched a variety of video clips; the analog approach produced none of the scaling artifacts commonly seen on low-cost contemporary displays.

The finished product takes up very little desk space while delivering a respectable image. Its analog input is compatible with antique cameras, game consoles, and any device that can output composite video, and a cheap converter makes it simple to connect to current sources. The hardwood mount keeps everything organized and the unit rock sturdy. The controls continue to respond as expected.
[Source]