Tom,
For what it is worth:
I have an intermittent him with my Heil mike, the one designed for 
Icom use.  Mine is intermittent and perhaps is based somewhere in the 
male plug, but I can't isolate it and some sighted, competent ham 
friends can't eyeball it either.  Its cable doesn't seem to 
disconnect at the base end of the mike like other Heil products so I 
can't try a replacement plug.  Should send it back to Bob and let him 
eeal with it.  My point is; perhaps we need to watch heil cables and 
plugs just a bit.  Or perhaps just a coincidence.
Pat, K9JAU