Onkyo 6 disc changer cd player NOS DX-C390

This looks brand new in the box like old store stock. It's been in storage for many many years and when I plugged it in it automatically started playing. There is a disc in it. The buttons on the front were very slow to respond at first but once it warmed up it seemed to play just fine. I believe it was used briefly by the first owner and then put back in the Box soon after purchase. I don't have a receiver or speakers to hook it up and actually test the sound. It's in the original box the paperwork and the remote control have never been opened or used. I believe the unit was used briefly many years ago and just sat in clean dry garage storage since then.