H7111 Field Maintenance Print Set

This document is a "Field Maintenance Print Set" for the Digital Equipment Corporation H7111 unit, specifically covering the H7111-A and H7111-B variations.

The H7111 is an uninterrupted power supply (UPS) designed to provide continuous power to a "time of day clock." It consists of a stepdown transformer, a regulator board, and a 5 Amp-hour sealed lead-acid battery. The unit is designed for installation in a standard 19-inch rack.

Key specifications and features include:

• Input: Operates at 0.1 Amp Max RMS current at 47-63 Hz. Voltage variations are supported: H7111A for 90-128V RMS and H7111B for 180-256V RMS. It includes a 1/8 Amp slow blow fuse for protection.
• Output: Provides 5VDC (+5%, 0-25 MA) and a "Battery DC Low" (BAT DCLO) signal. Connections are made via a 6-pin universal connector.
• Mechanical: Measures approximately 21" x 3.5" x 4.5" deep and weighs a maximum of 5 lbs.
• Timing: Includes a timing diagram detailing power, line voltage, battery DCLO, and charge cycles.

The document provides a comprehensive set of technical information for maintenance, including a table of contents, assembly drawings, detailed wire tables, circuit schematics (for the power supply and backup unit), extensive parts lists, and an engineering specification detailing its functional, electrical, mechanical, and environmental characteristics.