Function of the card:
CTRL- Inverter, Power - PNP
Quad Inverter
Complemented Transistor Resistor Logic (CTRL) is IBM's term for a form of resistor-transistor logic.
Part number:371487
PCB number:492793
Symbol:I, A, O
I: Inverter. Changes a positive input to a negative output, or vice versa.
Transistor type:033
References:
IBM 1620 Instructional System Diagrams, p485.
Pinout:
![]() |
A O4 B I3 C O3R D O2 E O3C F I4R G I1C H I4C J GND K I1R L O1C M -12V N +12VM P I2R Q I2C R O1R |
This page created by Ken Shirriff, 2015.
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. Images courtesy of Randall Neff. Much of this information was obtained through OCR, so don't expect complete accuracy. These pages are not associated with IBM in any way.
Creation time: Tue Mar 03 23:40:34 2015.