barit1 EGKK - I've never heard of "roughness" or vibs associated with this condition - and I've done a LOT of test cell runs w/PMC OFF. Unless there were some physical (FOD etc) damage that both dinged the rotors and disabled PMC, ... I don't see any connection.
With the PMC's inop possibly due to out of synch vibes if the N1's are not matched perfectly but only a guess.
