VAXft Systems Maintenance Guide

This document, the "VAXft Systems Maintenance Guide" (EK-VXFT1-MG.003) from Digital Equipment Corporation, published in May 1992, is intended for Digital Customer Services and other qualified personnel responsible for servicing fault-tolerant VAXft systems.

The guide focuses on the maintenance, troubleshooting, and repair of VAXft hardware, which achieves fault tolerance through duplicated components (two "zones" operating in lockstep). Key areas covered include:

• Diagnostics: Details the use of ROM-based diagnostics (RBDs), including power-on tests and interactive tests, to verify hardware integrity and isolate failures. It also introduces the Diagnostic Utility Protocol (DUP) for mass storage devices.
• Error and Error Analysis: Explains how the VAXft system detects and handles errors, and how to analyze system error logs for various components like drivers, memory, and WAN modules to identify issues.
• Troubleshooting: Outlines the maintenance strategy, emphasizing the role of Magnetic Fault Indicators (MFIs) and error logs in identifying faulty Field Replaceable Units (FRUs). It provides repair procedures, including how to clear module "broke bits," and specific diagnostics for WAN modules.
• Hardware Removal and Replacement Procedures: Offers detailed, model-specific instructions for the Model 110, 310/410, and 610/612 systems. These sections cover procedures for replacing logic modules (processors, memory, I/O controllers, WAN modules), system cables, power supplies, fans, peripheral devices (disk and tape drives), backplanes, and summary panels. Emphasis is placed on ESD precautions and proper zone shutdown/startup.
• Integrated Storage Elements (ISEs): An appendix provides guidelines for managing ISEs, including using the DUP utility for configuration, assigning DSSI unit numbers, and performing "warm swaps" (replacing components without interrupting system operations for supported models).

The manual aims to enable service personnel to effectively diagnose problems, replace faulty hardware, and restore system redundancy while maintaining continuous operation for VAXft applications.