Sony MZ-R55 Recording MiniDisc Portable MD Player Blue - No Sound

I’ve tried this with about five different ear phones and heed phones but can hear nothing. Things appear to be working otherwise though. Tacks displayed, skip etc… Cosmetically it looks rather goos other than some damage along battery. Even functionally it seems to work, at least until you try to listen to it. Battery pack I used to test isn’t included. The Sony battery terminals are not tested and don’t look perfect.