PCB Pinouts Atari System 1 Pinout

P101 - Power

1 - RTN
2 - + Sense
3 - +5vdc
4 - +10.3vdc reset (connected to 10.3v unreg from Audio Reg III PCB)
5 - -sense
6 - -15vdc
7 - N/C
8 - RTN
9 - +15vdc
10 - +5vdc
11 - +5vdc
12 - RTN

P104 - Credits/misc

1 - +5vdc
2 - coin counter
3 - coin counter 2
4 - N/C
5 - Self test
6 - aux coin switch
7 - N/C
8 - key
9 - left coin switch
10 - right coin switch
11 - GND

P105 - Sound

1 - Self test
2 - Right RTN
3 - Right audio
4 - Left RTN
5 - key
6 - Left audio

P108 - Video

1 - video RTN
2 - blue
3 - green
4 - red
5 - V sync
6 - key
7 - Csync
8 - Hsync