Digi002 peaks for no apparent reason

[GreenHat]

Hi!
Setup
I´m running the studio at a school with a setup of Digi002R, ProTools 7.3 and a MacPro
We just changed from a Digi001 / Windows system, which worked fine but was getting old.
As Preamps we use a TAC Scorpion desk by Amek running 8 ch lined to the Digi002 and 8 ch lined to an Alesis AI3 which then runs optically into the Digi002.

Problem
We´ve suffered strange current peaks on the analog inputs of the Digi002, but when run by the Alesis converter these problems seem to be eliminated! Using a Belkin Surgemaster to eliminate current peaks I thought I had solved the problem, but it seems that it´s only diminishing the problem, not solving it. I´ve taken care to make certain everything is hooked up to the same point to eliminate groundloops. This was not a problem on the Digi001.
I also tried the interface at home, running mics into the Digi002 for an hour, but without problems. Could there be some problem with internal cables in the Digi002 making it more sensitive in the studio (which has a lot more gear running than I have at home...)?!
Is there a sure way to test the unit?!
Thanks
Olle