Yes, start the process of troubleshooting this by checking source power first.
*** Williams System 11 Power measurements and test points ***
Logic power
MPU IJ17 Pins 4,5,6 = +5.03 VDC @8.1 mV AC ripple
U26/U27 ROM Pin 1 = +4.91 VDC
Audio power
MPU IJ17 Pin 9 = -14.04 VDC (Unregulated)
MPU IJ17 Pin 8 = +12.02 VDC (Unregulated)
Audio board U11 (U17 on Sys11B) Pin 8 -13.9 VDC @250 mV AC ripple
Audio board U11 (U17 on Sys11B) Pin 4 +11.8 VDC @50 mV AC ripple
Controlled lamp power
PS 3J4 pins 5,6,7,8 (Sys11A) or backbox bridge 6BR1 (Sys11B)= +15VDC to +18VDC nominal.
General illumination power
PSU 3J8 (Sys11A) or Interconnect board output 2P7 (Sys11B) = 4.5 VAC to 6.3 VAC nominal
Display power
3J5 pin 3 (Sys11A) or 3J2 pin 3 (Sys11B) = +90 to +110VDC nominal
3J5 pin 4 (Sys11A) or 3J2 pin 1 (Sys11B) = -90 to -110VDC nominal
Flipper power
Game [email protected] supply board outputs= +65 to +75 VDC nominal
Solenoid power
PS 3J3 pins 6,7,8 (Sys11A) +32 to +35 VDC
Interconnect board F1/F3 (Sys11B) +41 VDC
Interconnect board F4 (Sys11B) +75VDC
NOTES
Reference test games used:
Williams Pinbot - System 11A/D-8345-549 PS
Williams F-14 Tomcat - System 11A/Rottendog WDP-011A PS
Williams Taxi - System 11B/PinScore PJ-12246 Rev. B