my PI-1 board uses +5V only.
my all-in-one PI-1 X4 board uses 11VAC and 14VAC taps from the small transformer, but not the 69VAC.
therefore it could still run on a damaged transformer whose 69VAC tap often blows due to reverse insertion of A2P1 connector on the original GTB power supply..
in addition to this, my all-in-one PI-1 X4 board generates enough current on the 12VDC output available at the screw-clamp connector J1, so that it can directly power Boston Pinball's excellent displays without need for an additional power supply block.
see the attached picture: direct power to the displays or to the dimmer provided with each displays kit.