Remounting early trough opto boards on grommets

Steps

• Get six metal bushings (Williams 02-4975, or cut 3/16 inch or 5/32 inch OD brass or aluminium tube), six rubber grommets with a 3/16 inch hole (Williams 23-6626, outside 1/4 to 7/16 inch) and six #6 mounting screws 3/4 inch long. Three of each per board.
• Enlarge each board's mounting holes to about 1/4 inch (up to 7/16 inch to suit the grommets), avoiding traces. The centre hole is optional; two outer holes per board are enough.
• Fit the grommets and push a bushing into each. Each bushing should be very slightly shorter than its grommet so the screw clamps on the bushing while the board can still float.
• If you use all three holes with the newer A-16809-2 trough, relocate one big blue resistor to the board's rear face and drill an extra centre hole.
• Alternatively fit the A-18244 kit, which includes two new opto boards and the mounting hardware (the hardware is essential).

Systems

• WPC DCS

Games

• Indiana Jones: The Pinball Adventure
• Judge Dredd
• Popeye Saves the Earth
• Star Trek: The Next Generation

Related tips

• Random multiball or game never ends on early opto troughs
• Replacing trough transmitter and receiver optos
• Opto ball troughs from Indiana Jones on
• Full ball trough opto test in switch edge test
• Bench testing a trough transmitter board
• Games that came with Type 2 flipper opto boards
• Old and new WPC ball trough designs
• Turn ends while a ball is still in play in Final Frontier: flaky trough opto

Source: Repairing Williams/Bally WPC Pinball Games from 1990 to 1999, Part Three, Clay Harrell (pinrepair.com)