System 80B display driver chips 10939 and 10941
U1 and U2 are 10939 digit drivers: clock on pins 1 and 38, SOP pin 2, SIP pin 3, data DB0-DB7 on pins 6-13, outputs D40-D21 on pins 15-34, -45 V on pin 35, +5 V on pin 36, -15 V on pins 37 and 39, data-load on pin 40. U3 is a 10941 segment driver: -15 V pin 1, +5 V pin 2, segments n to e on pins 6-15, -45 V pin 16, segment d pin 17, c and b on pins 19-20, a on pin 22, clock pin 23, data-load pin 24. Both are hard to find but seldom fail.
The 80B display board turns 32 V AC into -45 V and -15 V DC; switch off before touching it and probe carefully with the power on.
Systems
Related tips
- System 80B display board connector A4J1
- System 80B alphanumeric displays dark: check the display board supply
- System 80 schematics' 'offset' voltages are DC bias for the display filaments
- Score display boards by generation
- Alphanumeric display board MA-644 parts
- Two alphanumeric display boards: glasses do not swap between them
- Guarding the fill tip on the back of a score display
Source: Repairing & Upgrading Gottlieb System 80 Pinballs from 1980 to 1989, Part Two, Clay Harrell (pinrepair.com)