I discovered that CODEC INPUT ATTENTUATION parameter was set to YES in the Remote box. How it got set to YES is unknown to me. This didn't look right to me.... so I set it to NO and also set the default values for CODEC OUTPUT GAIN and CODEC INPUT GAIN in both boxes. I re- adjusted CODEC INPUT GAIN in the CONTROL box to 40 and may reduce it further upon more monitoring.
I now have SSB audio working again using both headsets...the Heil and the CM-500.! The problem was the CODEC INPUT ATTENTUATION was turned on....I don't know how it got turned on or when.
I feel like a clutzh not having noticed this before. I guess its an issue of understanding what all these settings are actually for. It would have been helpful if there was a reference table listing out what the various settings are addressing.
Now that SSB is working and there is nothing wrong with the headsets I experimented with turing the BIAS OFF and then ON in the MAIN:MIC SEL rP.H BIAS parameter in the K3 Mini. Both headsets work whether BIAS is ON or OFF !...there is no change whatsoever!. This is telling me that if both mikes require bias in order to work then the function of taping "2" on the K3 is not actually turning BIAS OFF....it is merely changing the display. Maybe this is something for Elecraft to address
I am very happy the issue is solved with help and comments from a number of people . Your thoughs helped me correct the issue.
73 Frank VO1HP