The Jim Austin Computer Collection

Monroe 990

 

 

This is a classic early calculator, basic functions and Nixi tube display.

 

 

This is an example of one of the cards. The calculator uses chips with a few gates in each package (i.e. 8 gates) a modern chip will have millions of gates in the same package.

 

 

 

Here is a picture of the display tubes, called Nixi tubes. Each one is like s small neon light bulb.

 

 

Here you can see the Nixi tubes lit up.

 

 

 

This is the complete machine with the lid off.