That's not a big problem in itself. Under the Minolta logo on the front is a tiny window. Inside that window should be a tiny mirror. The mirror probably fell off. You may be able to hear it rattling around in there. Now if that mirror finds its way into a gear train or some other mechanism, THEN you will have a big problem. If you can locate the mirror and glue it back, problem solved. I did this recently with an XG-M--didn't even need to remove the top, just the front panel with the Minolta logo.
