Emax

Hello,
I bought a used Emax recently.  Every now and then I get a "Disk Not Formatted!" error when it's trying to load the software, and when it decides to move beyond the error, then the floppy seems to work fine.  Now it seems to be in a state where I can't move beyond the error and I can't load the OS.  I did successfully install an external SCSI jack and I was able to format a Zip disk a few days ago.  Is there OS Plus 1.0 on the Zip disk?  And if so can I get it to boot from the Zip disk?  I've tried to insert the floppy again and again, I've repeatedly rebooted the Emax, all I get is a crunching sound in the floppy drive and the error message like it's trying its best to read the floppy but just can't pull it off.  Is it time replace the floppy drive, I'm sure it's the original drive.
Thanks!
Robert