MP00010 MA20 Schematic Jul76

This document is the Field Maintenance Print Set for the Digital Equipment Corporation's MA20 Core Memory system.

It provides comprehensive technical documentation for various MA20 unit variations (e.g., MA20-AA, MA20-AB, MA20-GA, etc.) across different memory sizes (32K, 64K, 128K) and operating frequencies (60Hz, 50Hz).

The set includes:

• A detailed Table of Contents and Module Utilization data.
• Flow Diagrams illustrating operational cycles such as diagnostic, power up/down, and interleaved modes.
• Instruction/Setup Sheets (e.g., MA20 Deskew Procedure).
• Timing Diagrams demonstrating signal behavior, specifically for MA20 Interleave Mode 3.
• Interconnection Block Diagrams showing the overall system architecture and module connections.

• Extensive circuit schematics for key components:

  • 16K X-Y Drive (G235)
  • Control Boards (M8561)
  • Timing Boards (M8562)
  • 16K Sense/Inhibit modules (G114)
  • Stack Modules (H217B) and Stack Boards.
  • SBUS Terminators (M9005) and SBUS Cable Modules (M9006).

• Parts Lists for various components and overall unit variations.

• Wired Assembly drawings, AC-DC power wiring diagrams, and wire lists.
• A Drawing Directory and an Automatic Wire Tester (AWT) Revision Status sheet.

The document is copyrighted by Digital Equipment Corporation, primarily from 1975 and 1976.