The game reports the lamp/switch matrix fuses as bad, sometimes when they are actually good.

"Check Fuse F114/F115" (F106/F101 on WPC-95): step-by-step

Cause: Lost lamp or switch matrix supply: BR1 (D11-D14 on WPC-95) failed or with cracked pads, diodes D1/D2, regulator Q2, CPU board U20, or chips on an opto board.

Checks

• Game on, coin door closed. J101 pins 4 and 7 (J129 on WPC-95) should read 13-18 V AC from the transformer; if not, check the transformer and driver board Molex connectors.
• TP8 (TP102 on WPC-95) to ground should read 16-18 V DC; if not, replace BR1 (D11-D14) or repair its cracked pads.
• TP3 (TP100 on WPC-95) should read 12 V DC; if not, check diodes D1 and D2 (1N4004), then replace Q2 (LM7812).

Fix

• Still failing: replace CPU board U20 (ULN2803); if it failed hard also replace U14 (74LS374), or U23 on WPC-S (74HC4514) and WPC-95 (74HC237).
• Then, on games with an under-playfield opto board, replace all its LM339 chips in sockets.
• If the voltage is still wrong or BR1/D11-D14 run very hot, test every TIP107, then driver board U19 ULN2803 (U11 on WPC-95) and U18 74LS374 (U10 on WPC-95).
• Add the BR1 jumper wires for long-term reliability.

Systems

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

Related tips

• BR1 (D11-D14 on WPC-95) and the board around it scorched
• Switch matrix chips on the CPU board
• Switch matrix dead after a screwdriver slip under the playfield
• Row or column "ground short" errors
• Optos test good but still don't work: the opto board
• Lamp matrix faults with all lamp transistors good
• One switch does not work
• Why CPU U20 fails and how to replace it

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