Model D2 Plus Manual

Included in the box with the Model D2 Plus computer was a small 112−page user guide. This handy little guide assisted the end−user by providing an overview of the system, such as hardware components, software, and add−on cards. The manual included an overview of the exterior system anatomy, including the keyboard, monitor, rear panel, and mouse, and step−by−step directions on how to assemble and set up the computer system for the first time. If the user encountered any technical issues with their Model D2 Plus computer, the operator's guide served as the first stop for help, as it offered a technical glossary to define potentially unfamiliar terms and a troubleshooting guide that aimed to aid the user in rooting out an issue before visiting a Leading Edge dealer for service.

The Model D2 Plus was a capable machine for its time, built around the Intel 80286 processor that operated at switchable speeds of 8 and 12 MHz. The inclusion of a socket for an optional 80287 math coprocessor allowed it to handle complex numeric and graphic operations, especially for business and engineering applications. The system came with 1 MB of RAM standard, expandable to 4 MB on the motherboard, and supported both extended and expanded memory configurations. The D2 Plus also included six expansion slots, four 16−bit and two 8−bit, to accommodate future upgrades such as additional storage controllers, modem cards, or network adapters. Storage options were versatile, with support for 5.25" and 3.5" floppy drives as well as internal IDE−type hard drives. The machine's design placed emphasis on expandability and performance, while maintaining affordability for the small business and home computing market.

Physically, the D2 Plus offered a clean and practical hardware layout. The system unit housed the central components including the power supply, drive bays, and motherboard. On the front panel, the user found a power rocker switch, reset button, and keyboard connector, along with LED indicators and a keyboard lock for security. The rear panel contained a full complement of ports: two RS−232C serial ports, a Centronics parallel port, a dedicated mouse connector, and video outputs compatible with VGA, TTL, and analog monitors. Leading Edge provided a matching ANSI mechanical keyboard that included 101 keys divided into functional groups with dedicated function, editing, and numeric keys.

The setup and troubleshooting sections of the guide were particularly detailed, reflecting Leading Edge's understanding of the needs of new computer owners in the early 1990s. The assembly chapter outlined how to connect each component, from the keyboard and monitor to optional printers, and how to properly install MS−DOS, which was provided with the system. The manual also introduced users to the built−in SETUP program, which allowed configuration of system parameters such as memory allocation, video adapters, and installed drives. For users encountering issues, Chapter 6 provided an extensive troubleshooting guide that distinguished between hardware and software problems. It instructed users to check power connections, monitor signals, and cable attachments before seeking service. Additionally, the DIAGNOSE utility could run component−level tests on the CPU, memory, disk drives, and ports to isolate malfunctions. These diagnostic procedures gave users confidence and control over maintaining their systems, at a time when home computing was still an emerging field.

The Leading Edge Model D2 Plus Operator's Guide stood as more than a simple instruction manual, it walked owners through every aspect of setup, operation, and maintenance while introducing them to the fundamental principles of personal computing. The D2 Plus itself embodied the spirit of late 1980s and early 1990s PC design: robust, modular, and engineered for growth. The computer and its accompanying guide enabled users to explore computing with the confidence to properly setup, operate, and even diagnose simple technical issues.

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