MF20 TechMan

This document, a manual for the MF20 MOS Memory Subsystem (and MG20 where specified), provides service personnel with the necessary information for installation, operation, programming, preventive maintenance, and corrective maintenance.

The manual begins with an introduction to the MF20/MF20F, describing its general features (large capacity, high reliability, increased MTBF, reduced MTTR, on-line diagnosis, battery backup), physical components (logic assembly, master oscillator, power supply, various cables), and system configurations. It also lists system specifications and references to related documentation.

The site preparation and planning section details the steps for preparing a site for MF20/MG20 installation, including physical descriptions of internal and external options, mounting hole checks, preinstallation and final checkouts, and installation scheduling.

Installation procedures cover unpacking and inspecting the hardware, cabling summaries for different MF20 options, and a general overview of installation for various scenarios (e.g., adding a single MF20, expanding an existing system, adding external cabinets).

The operation and programming chapter explains how to bring the MF20 online, covering operator controls and indicators (circuit breakers, LEDs), manual operations, and program operations for configuring the memory system using diagnostic functions. It details eleven diagnostic functions for purposes like loading control RAMs, analyzing errors, diagnosing faults, and activating spare bit mechanisms, with examples of their use.

The technical description provides a functional overview of the MF20, including its conceptual block diagram, module block diagrams (M8579 storage module, M8574 write path, M8575 syndrome, M8577 address and timing, M8576 control and timing), and XBus interface. It also covers storage array organization, basic MF20 operations (read, write, read-pause-write, diagnostic cycles), and logic descriptions for error checking code (ECC), spare bit substitution, storage module operation, address response RAM, and timing RAM. The KW20 master oscillator and H7131 power supply are also described.

Preventive maintenance details recommended procedures and schedules, including required test equipment and steps for running SYSERR (system error report program) and TGHA (The Great Heuristic Algorithm) to identify potential problems. It also includes checks for KW20 clock, overtemperature sensors, door interlocks, battery backup, and system cabling integrity.

Corrective maintenance focuses on diagnosing and repairing faults in the MF20. It covers diagnostic software (11-based and 10-based diagnostics like DHKBF, DHKBG, MEMCON, DFMMH), general troubleshooting approaches (tops-down and bottoms-up), and subassembly removal/replacement procedures for the power supply, battery pack, KW20 logic module, and MF20 logic assembly. It also includes MF20 adjustment procedures for the KW20 regulator and clock deskew.

Finally, the document contains appendices on M8579 storage module geography, complex IC descriptions (DC008 data multiplexer chip, 4116/4864 MOS RAM chip), and the 11-based 10 diagnostic test structure, providing detailed information on these components and diagnostic methods.