In the bottom of the cabinet is the main transformer. On the right side of the transformer box there is a screw-in fuse holder for the line fuse. There is another fuse holder, on the left side, with a fuse for the general illumination circuits.
Hanging on the wood separating the coin box area from the rest of the cabinet interior is a Hantarex switch mode power supply, used to supply +5V to the video game board in the backbox and to run the cabinet fan for ventilation.
The Aux Output connector has +12V/Gnd on it, and is used to run the cabinet ventilation fan in some games.
The Input Connector has 220VAC and Ground connections from the main transformer.
The Monitor Power / Degauss connector is intended to drive a video game monitor, and has +135V on pins 1/2 and Degauss on pins 3/4.
The Output Voltage connector has +5V/-5V/+12V/-12V and Ground on it:
The pot in the centre of the case can be used to adjust the output +5V level.
In order to run a MrGame game intended for the European market (220V transformer) in the US, a "step-up" transformer like this one: