Apple 1

Using an Apple II Keyboard with an Apple 1 Computer

Apple II Keyboard with Mimeo

Many years ago, I worked on repairing an Apple 1 computer.  At the time, I needed a keyboard and came up with a simple wire wrapped circuit to translate the signals from the Apple II keyboard connector to that expected by the Apple 1 computer.

The Apple II uses the following connection:

       +---| |----+
   +5v | 1     16 | NC
Strobe | 2     15 | -12v
~Reset | 3     14 | NC
    NC | 4     13 | Data 1
Data 5 | 5     12 | Data 0
Data 4 | 6     11 | Data 3
Data 6 | 7     10 | Data 2
   Gnd | 8      9 | NC
       +----------+

The Apple 1 uses the following connection:

       +---| |----+
~Reset | 1     16 | +5v
Data 4 | 2     15 | Data 8 (connected to +5v)
Data 3 | 3     14 | Strobe
Data 2 | 4     13 | NC
Data 1 | 5     12 | Clear Screen (switch to +5v)
Data 5 | 6     11 | -12v
Data 6 | 7     10 | +12v
Data 7 | 8      9 | Gnd
       +----------+

Wiring the two devices together was easy, with one exception. The Apple II keyboard has no switch for clearing the screen. Rather than alter the keyboard, I left two wires exposed for the +5v and clear screen connections, which clear the screen when touched gently together.

Wendell Sander has instructions on how the Apple II keyboard can be wired to the Apple 1 computer’s keyboard input, as well as how it can be modified to use the repeat key as a clear screen key.

For those interested in a  board they can simply purchase and use, VintageMicros sells a small adapter board, which includes a clear screen button.