maybe its got the stiction?

maybe you could try this?

https://www.thinkclassic.org/viewtopic.php?id=263

other wise you can get a SCSI2SD for it.  I would say the Classic II is worth the investment.

http://shop.codesrc.com/index.php?route=product/product&product_id=58



or you could also get a Floppy emu,   The Classic II does have HD20 support built in.

http://www.bigmessowires.com/macintosh-floppy-emu/



I sell a modern HD vintage mac solution for $50each. Comes with proper 50 pin adaptor.

73gig,  2.5" 10K RPM, 8m Cache, Extremely Quiet, Extremely Fast, and the least expensive modern solution.



Or you could find old hd's on ebay, if you find your self an 80m or 160m, IBM

those seem to hold up much better then the Connor, Quantum variants.  The old HD, though

are just that.  might get one that last along time, might get it and be in the same board in 6 weeks.