Why does my floppy drive eject disks every time in Macintosh 512K?

I have a Macintosh 512k from 1984 and every time I insert a floppy disk, the machine spits it out after a few seconds and then displays an X on the screen. The floppy disks work in another computer and the computer beeps when it starts up (meaning it passed the hardware test) so I believe it is a dirty or damaged floppy drive.

However, I have no idea how to fix it or where to send it to be fixed. Not many 512ks were made in 1984 so I want to fix not replace it!