DVP Problems

[Randy A Thompson]

Used my DVP this past weekend (one of it's 3 outings per year). Need some 
suggestions.

My DVP has terrible hum.  If I put the rig in transmit without talking, 
the hum is more than 200W out (voice peaks at 1500W).  This is very 
noticeable to other stations and makes me sound like an Italian.

The hum was even worse before I added a ground strap between the computer 
and radio.

I am using the "official" cable from Harvard Radio.  My rig is an IC-765.
Mic is a Heil headset (although other mics have the same problem).

Randy, K5ZD