This page describes the IBM SMS card "GU", and is part of the SMS card database.

Function of the card:
Drum Sense Amplifier

Part number: 371526


AM: Amplifier. Provides increased strength to a detected signal or pulse.

References: IBM Standard Modular System, Component Circuits, p136
This page created by Ken Shirriff on Wed Sep 15 18:15:11 2021.

The information on these pages comes from a variety of sources, especially old IBM documents on, as well as information from the IBM 1401 restoration team, especially Tim Coslet's SMS data and Jim Hunt's data. Much of this information was obtained through OCR, so don't expect complete accuracy. These pages are not associated with IBM in any way.