CPU and driver board transistors by position
TIP122 (replace with TIP102; NTE261/NTE2343) solenoid and flasher drivers: Q6 to Q9, Q14 to Q17, Q22 to Q25, Q30 to Q33, and the odd numbers Q69 to Q79. TIP122 lamp row drivers: Q80 to Q87. TIP36c (NTE393): eight on the APDB, numbered Q1 to Q8, for 50 V coils, Big Guns and later only. 2N4401 pre-drivers (NTE123AP): Q2 to Q5, Q10 to Q13, Q18 to Q21, Q26 to Q29, Q34 to Q38, Q41, Q67 and Q68, and the even numbers Q70 to Q78. TIP42 (NTE197) lamp column drivers, switching +18 V: the even numbers Q52 to Q66.
Systems
Related tips
- Quick check of all TIP122/102 drivers before first power-on
- Solenoid driver transistor positions on the CPU and PPB boards
- Quick test for shorted TIP122/TIP102 drivers
- Where the WPC coil and lamp drivers sit
- Solenoid driver test at 2J9 and 2J11 with Leon's code
- How a WPC coil, flasher or lamp driver chain works
- Which transistor drives which WPC solenoid and lamp circuits
- How a coil or flasher is switched: PIA to TTL to pre-driver to driver
Source: Repairing Williams System 11 Pinball 1986 to 1990, Deel 1, Clay Harrell (pinrepair.com)