Yes, those little things are a pain. One of the MRC 6200’s I use had a loose part rattling around inside when it came in after being purchased on ebay. Before returning it I decided to open it up and take a look. The only problem with that was the “security” screws holding the unit together. I opened it with a pair of needle nose pliers and some spare time[banghead]. After I got it open though I discovered that the rattling was just a loose screw. After tightening that screw, I decided to make it easier to open the transformer up if it ever needs it again. So I mounted each of the screws in a hobby vise and cut a notch in them with a Dremel tool and cut off disk (Warning these get HOT, don’t use a vise with a rubber protector or you’ll melt it like I did). The notch is strangely enough the perfect size for a flat head screwdriver…[swg]. MRC might not like it but it’s cheaper then returning it to them to have a screw tightened.