Barclays Branch Controller

This document provides a comprehensive maintenance and diagnostic guide for the Barclays Branch Controller MK III. It includes:

• System Diagnostics: Detailed explanations of the internal diagnostic sequences at power-up, including normal, test, and auxiliary modes.
• Troubleshooting: LED display code tables that indicate fault conditions for various field-replaceable units (FRUs), including CPU, memory, and disk controller modules.
• Hardware Maintenance: Step-by-step instructions for accessing and replacing FRUs, such as the RD52 and RX50 disk drives, various PCBs, and power supply units.
• Installation & Software: Procedures for system installation, cable routing, and loading Barclays software using the Master Loader program.
• Reference Material: A complete list of FRUs, cable connection details, and procedures for reporting faults to support services.