Return to Early GE Computers
A Sampling of circuit cards from aShipped from about mid 1960 through about 1964
General Electric GE-225 Computer,
Buzz Heinzen, of Russellville, Arkansas kindly sent me a selection of GE-225 cards he has saved. Many years ago he purchased a GE-225, but he finally threw it, and the documentation out. :-((
The logic family is RTL (Resistor Transistor Logic) (inverting) , using "speed up" capacitors across the input resistors, and clamped output voltage.
These are "two sided" boards, ie, circuits on the two sides of the card, no internal layers or traces. The cards can be "keyed", have notches in the connector area, to prevent inserting the wrong card into the barriers in the socket. The cards are 5 3/8 inches wide, 10 7/8 inches long including connector pins, about 1/16 inches thick, and an unknown intercard distance.
This is a typical GE-225 gate circuit - as in a 11G11 card, 2 input NOR, very commonly used.
Unfortunately I do not remember exactly the voltages represented here as +6 and -6, nor am I able to read the value of the speed up capacitor - I'm guessing at about 60 pf
The logic voltage levels would be about 0.7 volts "LOW", 6.5 volts"HIGH". The edges were sharp enough so that a 15 foot wire I added for a paper tape punch would "ring", and needed to be terminated.
There is room for 21 pins in the first row, on 0.2 inch centers, and between those pins room for 20 more pins between the first row pins. The pins in the sockets are at a 90 degree angle and similarily split for a very positive sliding contact.
Type Model # Name Serial # Front Image
about 500KB !!
about 500KB !!
11G11 43D120594 G1 GATE BOARD A B065
Back Image 11G3 43D111213 G1 DIODE GATE C B855 Back Image 11G4 43D112483 31 GATE BOARD A C232
Back Image 1F4 599D922 G1
E A715 Back Image 1MA1 599D545 G1
D C356 Back Image 2ID1 599D506 G1 INHIBIT DRIVERS REV. C A209 Back Image 3DL6 43D115606 G1 DELAY BOARD A A848 Back Image 3R2 59D938 G2 (REV R) SHIFT REGISTER 464 Back Image 3SA1 599D665 G1
Back Image 4PD2 43D115364 G1 PULSE DISTRIBUTOR A316
Back Image 5BR1 43D111423 G1 BUFFER READ AMP 6 H061 Back Image 5HD1 43D113514 G2 HAMMER DRIVER D 406 Back Image 6G1 599D862 G1 GATE, GEN. PURPOSE A C268 Back Image