What the EM transformer supplies

The transformer steps line voltage down to about 6 V AC for lamps and 24 to 30 V AC for coils (50 V on 1970s Bally and on Williams before 1962). Williams from 1972, Bally from 1975 and Gottlieb from 1978 rectify some coil power to DC with a bridge rectifier. 1950s Genco games ran coils on about 18 V DC from selenium plates on the transformer.

Systems

• Electro-mechanical

Related tips

• Test an EM transformer
• Moving an EM transformer to the high tap
• High tap: a little more coil power from the transformer
• EM transformer high and normal tap positions by maker

Source: Repairing Electro-Mechanical (EM) Coin Operated Games to 1978, Part One, Clay Harrell (pinrepair.com)