A while back I hooked up my PC sound card to the Icom 746 pro using the acc1 port. I installed 1:1 isolation transformers inline of both the TX and RX lines to eliminate a ground loop. I noticed today when keying on AM and monitoring myself that I was getting a lot of popping and interference in the radio. I turned off the computer and it went away. Then I disconnected the computer connecting cable and it went away. Any ideas on how to eliminate this problem?