Abstract: An improved assembly design for a portable computer. A housing has a base member with a plurality of edge guides located along the side portions and a plurality of connector sockets arranged along the inner front portion. A matching circuit board has a plurality of forwardly extending plug margins which mate with the sockets when the board is fully installed in the edge guides. The board carries the main computer system electronic components and a rigid disk memory module. The keyboard assembly, floppy disk memory and power supply are all mounted to the under surface of the housing cover member, and the display panel is mounted to the top of the cover. The design enables quick assembly of the computer, and quick removal of the circuit board for repair.

Abstract: In a rotary printer control system, a dual mode servo for controlling the velocity and position of a rotary print wheel and a print wheel carriage is normally operated at a relatively high gain value. When the servo is switched from the velocity mode to the position mode, the length of time the servo remains in the position mode is monitored and, if this exceeds a predetermined maximum time period, the gain of the servo loop is switched to a relatively low value in order to reduce oscillations of the print wheel or carriage about the HOME position. The gain reduction is accomplished by inserting a supplemental R-C network in parallel with the high gain R-C network, and the range or ratios of the relatively high gain to the relatively low gain values is from about 10 to about 30.

Abstract: In a dual mode servo for a rotary printer control system for controlling the velocity and position of a rotary print wheel and a print wheel carriage, the analog counterpart of a digital desired velocity multibit character is generated by a bidirectional digital to analog converter so that the analog desired velocity signal has a maximum value range lying both above and below a zero reference level, thereby eliminating the need for additional analog level converting circuitry.