Function of the card:
SDTRL - SDTRL - 2 MC Oscillator
Open Collector 2MHz Crystal Oscillator (Note: probable errors in schematic for pins C and D)
Part number: 372231
The information on these pages comes from a variety of sources, especially old IBM documents on bitsavers.org, 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.