DECarray Service Guide

This document, the "DECarray Service Guide," is a technical manual published by Digital Equipment Corporation in June 1993. It provides comprehensive information and step-by-step procedures for servicing DECarray storage cabinets and their SF3x and SF7x series storage enclosures.

Key areas covered in the guide include:

1. Introduction: An overview of the DECarray system, including its capacity (up to six SF-series storage enclosures and one or two magazine tape ISEs), physical arrangement, and detailed specifications for the DECarray cabinet and both SF3x and SF7x storage enclosures (dimensions, weight, environmental limits, power requirements).
2. Theory of Operation: Explains the normal functioning of the storage enclosures and the DECarray, detailing DSSI (Digital Storage System Interconnect) node ID assignments, SF3x and SF7x operating modes (Through-Bus and Split-Bus), and the functions of various front and rear panel controls, labels, and indicators (e.g., Ready, Write Protect, Fault LEDs, DC power switches, AC power switch, line voltage selector). This section also includes crucial service guidelines and warnings regarding hazardous voltages and ESD precautions.
3. Troubleshooting: Provides procedures for verifying faults within the DSSI storage subsystem, isolating problems to specific FRUs (Field Replaceable Units) within the DECarray cabinet or storage enclosures, and using a troubleshooting chart that maps symptoms to probable causes and corrective actions. It also mentions the use of a DSSI Bus Meter for advanced fault isolation.
4. FRU (Field Replaceable Unit) Removal and Replacement: Offers detailed, step-by-step instructions for replacing various components:
   • DECarray Cabinet FRUs: Doors and the Power Controller.
   • SF3x and SF7x Storage Enclosure FRUs: This is a major focus, covering components like Disk ISEs (including "warm swap" procedures where applicable, and HDA/Drive Module replacements for SF7x), Operator Control Panels (OCPs), Power Supplies, Fan Assemblies, Transition Modules (TM for SF3x, TTM for SF7x), Backplanes, and various internal and external DSSI/power/OCP cables.
5. Post-Repair Checkout and Power-Up: Guides the user through procedures to verify normal operation of the repaired or replaced components.
6. Appendices: Includes lists of recommended spare parts for the DECarray, SF3x, and SF7x, and extensive cabling information (diagrams and tables) for various single-system, DSSI VAXcluster, and Stripe Set configurations.

The document is designed for qualified service engineers, emphasizing safety precautions throughout the procedures.