Some 80B driver boards use the coin counter transistors

On some 80B games Gottlieb put Q54, Q55 and Q56 to real use. You can recognize these boards because CR2, CR3 and CR4 are jumpers instead of diodes; don't borrow those transistors on such a board.

Systems

• Gottlieb System 80B

Related tips

• Test the driver transistors while the board is out for the ground mod
• What the System 80 driver board transistors drive
• One driver board fits every System 80, 80A and 80B game
• Driver board transistors that look stuck on in a test fixture
• Diode-test the driver board MPS-U45 and MPS-A13 transistors
• A meter test of a transistor is not conclusive
• Diode-test a driver board 2N6043
• Diode-test a driver board 2N3055

Source: Repairing & Upgrading Gottlieb System 80 Pinballs from 1980 to 1989, Part One, Clay Harrell (pinrepair.com)