DEC-10-HTMB-D TM10 Maint Sep73

This document is the TM10 Magnetic Tape Control Maintenance Manual, Volume I, for the DECsystem-10, published by Digital Equipment Corporation.

It serves as a comprehensive guide providing general information, operating instructions, programming details, technical reference, and maintenance procedures for the TM10 Magnetic Tape Control unit.

Key aspects covered include:

• Function: The TM10 acts as an interface between the DECsystem-10 core memory and up to eight magnetic tape transports (TU10, TU20, TU30, TU40/41). These transports support both 7-track and 9-track formats with various packing densities (200, 556, or 800 bits per inch) and speeds.

• Configurations:

  • TM10A: Data transfers between the tape control and core memory are handled by the program over the I/O bus.
  • TM10B: Data transfers are managed automatically by a DF10 Data Channel, bypassing the central processor, though the I/O bus is still used for status and control.

• Operation & Programming: Details on the TM10 indicator panel, tape formats (including NRZI recording, 7-track and 9-track data, parity, and Cyclic Redundancy Check for 9-track), tape handling guidelines, and PDP-10 I/O instructions for controlling functions like read, write, rewind, and spacing, along with interpreting various status bits.

• Theory of Operation: Explains the DF10 Data Channel interface, NRZI recording principles, and the internal logic of both TM10A and TM10B during initial setup, write, read, read/compare, and other operations, including how data is transferred and errors are handled.
• Maintenance: Outlines both preventive maintenance (mechanical checks, power supply verification, tape handling, cleaning procedures) and corrective maintenance (troubleshooting steps, diagnostic programs, signal tracing, and module circuit information).