I have one that is obviously only good for parts. It has no identification on it, is wind-up, and appears to have a broken main spring (it won't wind, no matter how long you twist the stem). Somebody was already inside, and apparently had it running. What looks like tape on the back cover is really a peace of clear plastic cemented in place. Free to you, or anyone else who can use it. Is it like yours? See attachment.
