You can also use a computer power supply to benchtest the CPU board - Clay's guide shows how to hook it up.

Basically you need to connect the CPU board to a known good power supply voltage(Arcade or Computer), with nothing else connected, and see if it boots or not.
If it won't boot on the bench then you know the problem is definitely on the CPU board and not on your power supply board.

You can then either send it for repair or attempt repairs yourself, but read Clay's Beginner guide before attempting any repairs. http://www.pinrepair.com/begin/index.htm
If you don't have much PCB soldering, or more importantly, DESOLDERING experience you are probably better to send it out, as these boards can easily be damaged.