What to lubricate in an EM game (very little)
EMs mostly run dry, and too much lube does more harm than too little. Metal rubbing on metal may get a light film; nylon against metal or nylon gets none. Never lubricate coil plungers or sleeves (even metal ones) or score motor gears. In practice only stepper wiper parts and a few metal pivots need it.
Systems
Related tips
Source: Repairing Electro-Mechanical (EM) Coin Operated Games to 1978, Part One, Clay Harrell (pinrepair.com)