At the risk of rehashing the "pin 1" problem, I came across a situation while doing some preventative maintenance on our A & H GL3800 that has me curious. In addition to intermittent static/cutouts on various channels (that we are addressing with a thorough cleaning of ribbon cable, exercising inserts and switches, etc) we occasionally have minor RFI-picking up the local AM station. I know there are many avenues this could find its way in by...
I also decided to replace some of the XLR jacks and may do all, since some of our issue seems to be at this point. The factory jacks are Neutrick with pin 1 and shell connected. It makes sense that connecting the shell to the chassis as directly as possible would help with RFI(as mentioned in some of the references I found). When I desoldered one of the jacks the "connection" between pin 1 and the shell literally fell apart (it is just a spring tension connection). The shell grounding connection is also designed to be connected to the chassis through one of the 2 mounting screws for the jack. Interestingly, A & H only uses one screw per jack-and the one that should ground the shell directly to the chassis is not used.
Something to consider, or not? Not trying to attack A&H-the board has served us well IMO it was a very good investment.