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

Function of the card:
N to P Converter (no loads)
Alloy-field replacement,am card
Alloy-One Way ā€œNā€ Block

Listed in 1401 SMS card usage

Germanium alloy transistors were an early type of transistor, faster than the earlier grown-junction transistors.

Part number: 371203

Field replacement part number: 370904

PCB number: 491139

Used in: IBM 1401, IBM 7090, IBM 7070


C: Converter. Used to translate from one voltage level to another, or to change the amplitude of the voltage swing about the same reference level.
IBM SMS card type AM 371203 IBM SMS card type AM 371203 IBM SMS card type AM 371203 IBM SMS card type AM 371203

Image courtesy of Henk Stegeman

References: 1_2 SMS Cards, pp28,65
Coslet data
This page created by Ken Shirriff on Wed Sep 15 18:15:09 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.