Eddy sensor board R1 values by game

R1 on the eddy control board centres the trim pot for the size of sensor coil. STNG, and two eddies on Theatre of Magic, use the small sensor with R1 = 4.7k ohm. Roadshow and the Theatre of Magic trunk use the larger sensor with R1 = 2k ohm. When moving a board between games, change R1 to suit; with the wrong value the board may still work but with little adjustment range.

Systems

• WPC DCS
• WPC-Security (WPC-S)

Games

• Red & Ted's Road Show
• Star Trek: The Next Generation
• Theatre of Magic

Related tips

• Eddy sensors: electronic ball switches under the playfield
• Cannon won't turn on the third multiball shot though it tests fine: flaky opto wire
• All playfield optos dead after replacing one opto: failed 16-opto board
• Turn ends while a ball is still in play in Final Frontier: flaky trough opto
• Indiana Jones to Demolition Man games have two LM339 opto boards

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