Hi, I've acquired a friend's minidisc recorder, a Sharp MD-MS 702 MK. I can plug a stereo mic into it (a Sony ECM-939LT) and hear what is happening around me whne I hit the record button on the Sharp. I then hit enter or the play button and it seems to be recording (the counter runs) but when I try to play that recording back, I hear nothing, even though the volume is all the way up or I vary it. It does play pre-recorded content just fine so I know it can play some discs. Am I doing somet