General illumination strings

GI runs on 6.3 V AC from the transformer, through a fuse and a triac on the driver board, to up to five strings of about 18 bulbs (90 maximum). On WPC-95 only three strings go through triacs; the other two are always on.

Systems

• WPC Alpha-Numeric
• WPC Dot Matrix
• WPC Fliptronics
• WPC DCS
• WPC-Security (WPC-S)
• WPC-95

Related tips

• No GI at all
• One GI string is out
• Several GI strings dead after a connector repair: lifted pads at J115
• GI string dead after connector replacement: broken traces
• GI strings won't dim in the GI test
• All GI out (playfield and backbox) with good fuses and plugs: reseat the CPU ASIC and ROM
• One GI string dead though the board and fuse test fine: burnt connector in the cabinet
• Two GI strings still dead after fixing a burnt J120: broken pads and traces

Source: Repairing Williams/Bally WPC Pinball Games from 1990 to 1999, Part One, Clay Harrell (pinrepair.com)