Lamp data and select lines: MPU J1 and lamp driver J4 pins
On the lamp driver board, J4 pins 14-17 (AD0-AD3) pass R76-R79 to pins 2, 3, 21, 22 of all four 4514s, and J4 pins 7, 6, 5, 4 (PD0-PD3) pass R74, R73, R72, R71 to pin 23 of U1, U2, U3, U4 respectively. On the MPU, J1 pins 15, 14, 13, 12 (AD0-AD3) and 16-19 (PD0-PD3) pass R70-R77 to PIA U10 pins 2-9.
Systems
Related tips
- Lamp driver board: which SCR drives which connector pin
- Controlled lamps stuck or not flashing: reflow MPU and lamp driver header pins
- Substitute SCRs for the lamp driver board
- Lamp driver, auxiliary lamp driver and display driver test points
- Lamp driver board layout: SCRs, decoders and connectors
- One insert lamp dead after nearby work: bad pin in the lamp driver IDC connector
- Controlled lamps flicker or stay out after fitting a replacement lamp driver with LEDs
- Some controlled lamps out: cold solder joint on the lamp driver board connector
Source: Repairing Bally Electronic Pinball Games from 1977 to 1985, Part Three, Clay Harrell (pinrepair.com)