Black Hole: fitting a heavy-duty 12 V gear motor

Steps

• Choose a 12 V continuous-duty gear motor of about 1.5 rpm; the disc should turn near 1 rpm.
• Take off the disc, loosen the set screw and remove the shaft adapter, then remove the old motor and bracket. Take the CPU board off the light board for room and move the harness aside.
• Hold the gearbox to the back of the light board, motor body to the left, shaft centred in the hole, and mark the four screw points clear of lamp wiring.
• Drill four 3/16" holes. Mount the gearbox with four 1.5" #8 pan-head sheet-metal screws, with a rubber washer each side of the board to stand it off the wiring and cut noise. Tape over the gearbox face and any bare wires beneath it.
• Drill the disc adapter out to suit the larger shaft (about 5/16", check the shaft first), ideally on a drill press.
• Mount the adapter near the outer end of the shaft while leaving room for the set screw to bite, and space the disc forward with washers and 1" 6-32 screws so it clears the lamps and the glass.
• Refit the CPU board, harness and connectors, and dab silicone on the screw tips at the back so they cannot cut the harness.
• If it turns too fast, put a resistor of about 10 ohm 10 W in series with the power lead and insulate it. Connect to the original motor wires.

Systems

• Gottlieb System 80

Games

• Black Hole

Related tips

• Black Hole playfield-mounted transistors Q1 to Q5
• Black Hole DIP switch traps
• Black Hole and Haunted House third relay ("U")
• Black Hole up-kicker on a pop bumper driver board
• Black Hole solenoid test order (manual correction)
• Black Hole driver board: which transistor runs which coil
• Black Hole up-kicker rarely needs the driver board conversion
• Correct up-kicker coil for Black Hole and Haunted House

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