There was no on/off switch for this era of Williams machines. To turn on the power, plug in the power cord and press the flipper buttons or close the coin chute switch (dropping a coin in the coin slot) and the machine will turn on. To turn off the machine, slap the bottom of the cabinet or unplug the power cord. You can always install a traditional on/off switch at the bottom of the cabinet if needed.

Most likely there are dirty relay switches that are prevented the score reels from resetting. First check if all the Jones plugs are clean and seated tightly to their connectors. The Jones plugs are at the ends of the wiring harness that connect the backbox and playfield to the main cabinet.

For your photo of the stepper, it looks like it's a continuous stepper, so it only needs one step up solenoid - so no missing parts.

The smaller globe lamps were originally installed in the 1960s. These smaller globe lamps are still made, but they are made in a variety of voltages. The modern, taller lamps are mostly used now. It's recommended that #47 lamps be used in the backbox to reduce heat issues that could damage the backglass paint.

Check out Clay's pinball repair Web site for complete information about repairing EM pinball machines:

http://www.pinrepair.com/em/index.htm

The transformer discolors with age and heat cycles. Your transformer looks fine...

Serial number should be printed on the paper tag on the upper left of the playfield on the playfield ball arch cover.

Power to the match lamps is controlled by the game over relay. If power is reaching the game over lamp, it should be getting to the match lamps since that game over switch controls power to both. There should be a number match on/off plug in the backbox - is the plug tightly seated to the jack? Also, check the number match stepper unit to make sure it rotates smoothly and that the switch contacts are clean. Other issues could be burned out lamps and faulty lamp socket.

The consensuses of the forum over the years is that these 60s era EM machines look best with white rubber rings and the original incandescent "white" lighting - #44 or #47 lamps, and very limited color lighting. Although, they now make LED lamps that simulate incandescent "white" lamps. All personal preference, though.

Only one credit should be subtracted from the credit unit when the credit button is pressed. Check the operation of the credit unit. Manually push in the credit unit reset solenoid plunger. Credit wheel/stepper should click down to the next position and subtract one credit. It's common for a credit unit to get gummed up from old grease. Thus, the credit unit would need to be disassembled and cleaned. Reassembly would only require very limited amounts of grease/lubrication.