Problem w/Clearaudio Nano phonostage

Hey, 
Looking for some input on an issue I am having with my Nano v2. 
It's a small little lad that sounds great, running it into a pair of AudioEngine A5+ speakers. 

The Problem I have been having is that it won't transduce the full 
sound from TT needle to the A5s. I can only hear a faint intermittent 
bit of the record but a more prominent double thud out of the speakers.

I can see the 5" woofers move when the double thud hits it, and it is not a
regular rhythm, but occurs every 2-3 seconds. I disconnected the TT from the Nano
and switched outthe ICs I am using (from Nano to A5s) to rule down the possible culprit. 

So the problem seems to be somewhere from the body of the Nano to the 
wall wart. I'm concerned that it may have been hit by a power surge, as we 
have had seem recently, and wondering about any surge protection from 
the Nano itself, b/c it unfortunately was not plugged into a surge protector.
thanks!
Gary