I just bought a new Meopta Opemus 6a with the Color 4-ES head today. I've finished setting it up, but noticed a rattling noise inside the head. When I opened the head, there was a loose piece (see photo). Anyone know what this piece is supposed to do, or where it's supposed to go? That aside, the enlarger works fine (or seems to). Any help would be most appreciated. Thanks! Also, the color head has two levers on the sides. One is the white light switch (move filters out of the light path), the other one I'm not sure. I can turn it round and round, and it does nothing.