need help with fizzing or interference in my mkh 40 mic

["bleublancrouge24" bleublancrouge24]

i'm having something that sounds like fizzing noises coming from my mkh 40 mic 
at times. sometimes it's there, then later on that day or another day it's not. 
it will also change the fizzing quality if i move the mic around, pointing it 
up or down or in other directions. (yes i've switched out the cables)

i know that back in 2011 vicki have noise problems with her mkh20. that was an 
earthing problem.

i'm wondering if it's the same thing. this is an older mic that used to be 
owned by a radio station in switzerland.

if any of you know what i'm talking about i'd like some help to see how i can 
fix this problem. i'd like to send you a clip of what the noise sounds like to 
help pinpoint what's wrong.

thanks in advance.
cheers,
P.