Quoted from schudel5:Most Williams from that era have a bridge powering the pops, flippers and slings. There is a fuse and capacitor in the circuit as well.
Only Gottliebs ever had DC flippers
Quoted from 3rdaxis:I think "20" is the gauge and "300" is the winding
Correct
Quoted from 3rdaxis:But what is 28-40?
It's for the hold winding. Flipper coils have two windings, one for the power stroke and one for the hold.
I'd recommend you just order the proper flippers for early SS williams (eg, Hot Tip, Lucky Seven). All SS games have DC flippers, and these use the same mechs as the EMs, so technically you'll have a coil designed for DC strengths.
Also try opening the EOS a bit