Are you sure it's together correctly? (mechanically speaking). That flipper enable coil was one of the few things wrong with mine when I got it. Thankfully it was just out of spec gap wise and a little adjusting handled it - but the coil pulls that such an oh so tiny margin the on/off adjusting is maddening. If there is too much tension or something isn't moving correctly, the little coil may be ok and just not have enough power to pull in
If the coil isn't working at all, are you sure you put the wires back on right when you switched it? If it's reversed with the diode, that would be an issue.