HSC Service Manual

This document is the EK-HSCMA-SV-001 HSC Service Manual, published by Digital Equipment Corporation in August 1988. It serves as a comprehensive technical guide for field service personnel on the service and maintenance of Hierarchical Storage Controllers (HSC), specifically covering the HSC70, HSC50 (modified), and HSC50 models.

The manual is structured to provide detailed information across various maintenance aspects:

1. General Information: Provides an overview of the HSC architecture, including hardware components (modules, buses, interfaces), internal software (control program, various managers like MSCP, CI, Disk Error, TMSCP, Diagnostic, Utility processes), physical specifications, and the overall maintenance strategy focused on Field Replaceable Units (FRUs).
2. Controls and Indicators: Details all operational controls, indicators, and switches found on the Operator Control Panel (OCP), inside the front door (for RX33 and TU58 drives), maintenance access panel, and individual logic modules, explaining their functions for monitoring system status and initial troubleshooting.
3. Removal and Replacement Procedures: Offers step-by-step instructions for safely removing and replacing FRUs across all HSC models, including power supplies, disk and tape drives, logic modules, airflow sensors, and power controllers, emphasizing safety precautions like power removal and anti-static measures.
4. Initialization Procedures: Explains how to connect console terminals and initialize HSC systems, detailing the various boot diagnostic tests (INIPIO, Init P.ioc) and their requirements, operations, and the interpretation of fault codes displayed on the OCP.
5. Device Integrity Tests: Describes a range of software-based diagnostic tests (e.g., ILRX33 for RX33 drives, ILTU58 for TU58 drives, ILMEMY for memory, ILDISK for disk drives, ILTAPE for tape devices, ILTCOM for tape compatibility, ILEXER for multi-drive exercising). For each test, it covers system requirements, operating instructions, progress reports, and detailed error message formats for fault isolation.
6. Offline Diagnostics: Provides in-depth information on comprehensive offline diagnostic tools, including the diagnostic loader, WCS loader, and specialized tests for cache, bus interaction, K-modules, memory (including refresh), RX33 drives, and the OCP. It details their boot procedures, error reporting mechanisms, and troubleshooting steps.
7. Utilities: Outlines the usage of various offline utilities such as DKUTIL (Disk Utility) for displaying disk structures and data, VERIFY for checking disk architectural integrity, FORMAT and RXFMT for formatting disk media, VTDPY for video terminal display of system statistics, and DKRFCT for managing bad block replacement tables.
8. Troubleshooting Techniques: Offers a systematic approach to diagnosing and resolving HSC issues, categorizing errors into initialization and system-type problems. It provides detailed interpretations of OCP fault codes, module LED indications, software error messages (MSCP/TMSCP, BBR, out-of-band), hardware-detected traps (like NXM, Parity, Level 7 K Interrupts), and an alphabetical listing of common software error messages with suggested field service actions and probable FRUs.

The document also includes several appendices with supplementary technical information, such as internal cabling diagrams, detailed exception codes and crash dump interpretations, generic error log field definitions, and hardware revision matrix charts for all specified HSC models.