Black Hole: run the backglass motor only during a game (transistor method)

Steps

• Cut the green ground wire to the motor and connect the motor side to the emitter of a TIP125.
• Fit a 1N4002 from the TIP125 collector (non-banded end) to the green/yellow harness wire that used to go to the motor (banded end).
• Fit a second 1N4002 from the TIP125 base (non-banded end) to the white/red/gray wire at driver board connector A3-J3 pin /A (banded end). Seen from the front of the board, that is the rear pin third from the right.
• Put an inline connector in that wire so the head can still be removed.
• The motor now gets its ground only while the game over relay is energised. A switch added to the game over relay that breaks the motor power does the same job mechanically.

Systems

• Gottlieb System 80

Games

• Black Hole

Related tips

• Black Hole driver board: which transistor runs which coil
• Haunted House driver board: which transistor runs which coil
• Black Hole playfield-mounted transistors Q1 to Q5
• Black Hole: new motor on the original gearbox
• Coil stuck on that is driven through a playfield-mounted power transistor
• System 80 driver board transistor types
• Flippers dead during play: check the "U" relay
• Black Hole backglass disc not turning or noisy

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