So, I don't usually enter the mystical land of the soundies, being much happier in the mystical land of the lampies, but I thought I'd share this story, since it may help someone else down the line. Our story begins with me borrowing a 5 mic system from a community theater (I actually put this system together for the community theater a few months back for a show I designed there). The system is 5 SLX microphones (the bodypack transmitters) and receivers (plus an antenna distro system, though thats not important to this story). So, I got the system together and was checking it, and one of the microphones sounded quite unhappy. Even standing right next to the receivers, there was a lot of low frequency noise, that seemed to happen when I moved (I mean a lot of LF noise). I checked the mic, and I was still getting this loud noise. I unplugged the microphone from the pack, and the noise didn't stop. Great. I found out that if I shook the pack, I got this horrible low frequency noise through the system. Well, only needing 4 of the 5, I labeled that NFG and moved on. A few days later I had some free time during the rehearsal, so I decided to have fun and open up the pack to see if I could find the problem. I opened it up, and found that the little metal RF shielding inside the pack was no longer attached to where it should be. It had somehow loosened its self and was flinging its self against the circuit board. Hum, well that could be a problem. I put it back where it belonged and bent the ends of the metal back down to secure it, put the pack back together and checked it. Problem solved. (Site note: It looked like it was just secured by bending the metal edges, I saw no glue residue or anything else) In the attached picture, it is the (slightly dented) metal piece covering the circuit board. On another side note, these packs are put together very well. Shure does a very good job with their designs. Oh, and I saw (and heard) no lasting damage from what I assume was this RF shield shorting-out the circuit board.