Your voltages without the PCB plugged in should be roughly the same as what they will be with it plugged in. If not, then there's a problem.
You want to first check the voltage at the 10.3V test point on the AR, without the game board plugged in. This should be in the range of 12-13V DC. This is the input to the AR, coming from the brick. If you do not have 12-13V here, then the problem is with the brick, and it's most likely the bridge rectifier.
If you do have 12-13V going into the AR, and not +5V out, then the most likely problem is a bad 2N3055 transistor, which is the big one in the middle of the heatsink. Replace that first.
If that doesn't fix it, you should then replace the LM305 regulator (the 8-legged can-looking thing). One of those two things will almost certainly fix it.