When the Apple II computer became available in 1977 it did not ship with a display monitor. Apple could not get FCC approval for a Radio Frequency (RF) Modulator connecting the computer to a standard Television. Instead Apple partnered with another company, M&R Enterprises of Sunnyvale California, to create the standalone Sup’R’ Mod. This device, one of the first Apple II peripherals, connected an Apple II computer to a standard television, presenting a color signal on UHF channel 33.
Apple’s first monitor was the Apple Monitor III (manufactured by Sanyo), designed to complement the Apple III computer introduced in 1980. Apple’s first monitor designed specifically for the Apple II computer (Apple Monitor II) was introduced in 1983. Prior to 1980 Apple I and Apple II owners used a variety of monochrome NTSC composite CRT monitors, many of which had been designed for use as video monitors. The Sanyo VM-4092 and VM-4209 monitors were often used with Apple I and early Apple II computers. These monochrome monitors could be powered by either 12V DC (useful for mobile applications) or 120V AC and were originally designed for monitoring video production or security surveillance video. They initially used BNC connectors as their video signal input ports, later adding RCA connectors.
By the 1980’s a number of companies sold NTSC composite CRT monitors designed for the burgeoning personal computer market. Popular brands included Amdek, Apple, Dynax, Princeton, Sakata, USI and Zenith.
Monochrome CRT monitors used either white, green or amber phosphors. The majority of composite CRT monitors used a green phosphor (P1), in part because of longer persistence. Amber CRT displays (P3 phosphor composed of Zn8:BeSi5O19:Mn) were thought to reduce eye strain. On virtual CRT displays the RGB values 255, 191, 0 will approximate amber CRT display.
In 1982 I purchased my first ‘home computer’: a Franklin Ace 1000 (Apple II Clone), with two Lobo 5.25 floppy disk drives and a USI Pi3 12 inch amber display monitor. The USI Pi3 amber composite monitor (USI Industries, Brisbane, CA), is a 12 inch high resolution 20 MHz CRT monitor capable of displaying 80 columns x 24 lines of sharp text.
I recently acquired a vintage USI PI3 amber monitor (Model VM-1230, manufactured in 1982). The screen has no burn-in and it works well with the Videx 80 Column card in my Franklin Ace 1000. In the photo below the text looks yellow but in reality it is amber/orange.
The USI Pi3 monitor has a number of external controls (located in a compartment below the screen): Horizontal Width, Focus, Horizontal Hold, Brightness, Contrast, Vertical Hold, Vertical Size and Vertical Linearity. There is an interesting video on Adrian’s Digital Basement II discussing the related USI Pi4 amber monitor.
I have been unable to find either a user manual or service manual for this monitor. If you know where I can find either, please let me know.
Henry Lowe 