There are connectors on the filterboard on the short side of the main cage that provides the power-in. They'll be the ones with white and yellow wires. White is GND and yellow is +5v. I usually poke the probes of my multimeter into the backs of these connectors beside the wires (the black probe into a white one and the red probe into a yellow). You can do this whilst the game is off to avoid shorting anything before turning the machine on.I don't know how/where to test on the filter board
A better place to measure the voltage is on the board itself but I can't remember where off the top of my head. The filterboard should be good enough though.




