Diode-testing the 12P06 strobe MosFETs

Steps

• The strobe MosFETs Q33-Q44 are P-channel 12P06, IRF9530 or NTE2383.
• Power off; remove the board or unplug P5 and P6. Meter on diode range.
• Polarity is reversed from the coil parts: red lead on the tab or centre leg, black on the lower leg. Expect 0.4 to 0.6; 0.2 to 0.3 means replace.
• Check the upper leg too, where the guide expects no reading; a 0.2 to 0.3 reading means replace.

Systems

• Gottlieb System 3

Related tips

• Diode-testing the 12N10L/IRL530 MosFETs
• Spare MosFETs for the driver boards
• Only logic-level (L) MosFETs work on the driver board
• Coil MosFET ratings and substitutes
• What the A3 driver board drives
• Proving the driver board's switch strobes
• A whole row of eight switches dead
• Cue Ball Wizard: coils holding on weakly (BUZ72L MosFETs)

Source: Repairing Gottlieb System 3 Electronic Pinball Games from 1989 to 1996, Clay Harrell (pinrepair.com)