Dectape Control Type 552 Instruction Manual

Summary

This manual provides comprehensive technical and maintenance information for the Digital Equipment Corporation (DEC) Type 552 DECtape Control. The system is designed to facilitate high-speed data transfers between DEC computers (specifically the PDP-5 and PDP-8) and up to eight DECtape transport drives (Type 555 or TU55).

Key topics covered include:

• System Overview: A general description of how the Type 552 control interfaces with computers and transports, utilizing data-break facilities for efficient I/O operations.
• Principles of Operation: Detailed explanations of the DECtape recording format, mark-channel usage for addressing and control, and the eight specific operational modes (Move, Search, Read/Write data, etc.).
• Control Logic: A technical breakdown of the interface between the computer and the control, including register operations, status signals, and timing logic.
• Circuit Description: Analysis of both conventional DEC logic circuits (gates, inverters, flip-flops) and specialized circuits used in the control (read/write amplifiers, delay modules, and clock circuits).
• Maintenance: Preventive and corrective maintenance procedures, including diagnostic checks, module replacement guidelines, and instructions for using marginal check voltage supplies to identify failing components.
• Reference Material: A comprehensive list of engineering drawings, schematics, and semiconductor substitution tables required for system servicing.