I tested as suggested on the CPU board.  With the DMM set to X.XX on AC I got readings of 0.02vAC on the -12v and 0.25vAC on the +12.  On the board (at the test points) it states unregulated so I don't know if this is a good indication.  On the +5v on the CPU board I got readings of 0.00vAC.

There has to be something worn / not working somewhere as Mark's LAH at the factory is 80% quieter than mine...

Hmmm...