A D107-001 or D107-003 board fitted to one of the first System 80 games does not start; the playfield tilt relay flickers on and off all the time.

Single-ROM CPU board won't boot in an early two-PROM game

Cause: The two original 512-byte PROMs cannot just be plugged into PROM1/PROM2 on a D107 board; it needs one 2716 holding the code laid out differently. A flickering tilt relay generally means bad game PROM code or a bad PROM socket.

Checks

• Check which revision the board is and what is fitted at PROM1/PROM2.

Fix

• Burn a 2716 with the PROM1 and PROM2 images repeated twice in order (PROM1, PROM2, PROM1, PROM2, joined as one binary file) and fit it at PROM1.

Systems

• Gottlieb System 80

Games

• Circus
• Counterforce
• The Amazing Spider-Man

Related tips

• Later single-PROM CPU board won't boot in an early System 80 game
• U2/U3 rules ROMs decide which system a CPU board runs
• Which System 80 CPU board goes with which games
• System 80 CPU board main chips
• System 80 and 80A CPU boards swap only with the matching U2/U3
• Reading the System 80 CPU DIP switches
• A System 80 board boots without its 5101 RAM
• Random errors on early System 80/80A CPU boards: add the R/W pull-up

Source: Repairing & Upgrading Gottlieb System 80 Pinballs from 1980 to 1989, Part Two, Clay Harrell (pinrepair.com)