Test a 2N6122/TIP41 lamp row transistor with a meter

Steps

• Meter on diode test, transistor lettering facing you.
• One lead on the left leg (base).
• Other lead on the centre leg (collector, or tab): expect about 0.4 to 0.6 V.
• Other lead on the right leg (emitter): expect about 0.4 to 0.6 V.
• A TIP41 can replace a 2N6122.

Systems

• Williams System 3
• Williams System 4
• Williams System 6 / 6A
• Williams System 7

Related tips

• Test a 2N6427 (MPSA14) lamp matrix transistor with a meter
• Test a 2N5060 lamp matrix SCR with a meter
• Replace the TIP42 lamp column transistors with IRF9Z34N MOSFETs
• Driver board transistors and what they drive
• Replace burnt 3 watt lamp resistors with 5 watt
• Spare transistors for driver board and power supply
• Test a TIP120/TIP102 solenoid driver with a meter
• Coils 1-8: connector, transistors, PIA pin

Source: Repairing Williams System 3 to System 7 Pinball 1977 to 1984, Part Two, Clay Harrell (pinrepair.com)