Projects › VCR139A 405-line Television Monitor
VCR139A 405-line Television Monitor
Under constructionTelevisionCRT405 lines
Last updated 28 September 2026
The VCR139A is a small electrostatic cathode-ray tube, originally used in wartime radar indicators and later in countless post-war amateur oscilloscopes and 'first television' builds. This project turns one into a working 405-line television monitor.
The design is built up one module at a time: CRT supply and divider, sync separator, line and field timebases, deflection amplifiers, video amplifier, spot-kill, audio, and a Band I receiver for the 405-line signal from the standards converter. Addendum A adds automatic field height so the same monitor also displays 525-line NTSC.
At a glance
| CRT | VCR139A, 4 V heater, electrostatic deflection |
|---|---|
| Standard | 405 lines / 50 Hz (525/60 via Addendum A) |
| Signal | Composite video or Band I RF |
| Status | Tubes tested; modules being built |
Block diagram
Click a drawing to open it full size.
Documentation
The full design report, schematics and parts list will be published here once the project has been built, tested and filmed.