Just an update- I have gotten  a couple of different slim floppy drive brands now, and they worked fine with the Floppy Converter.
I have now tried:
TEAC Model: FD05HG
Sony Model: MPF820
NEC Model- FD1238T
All worked.
I am beginning to think most slim floppy drives should work.
If the wrong flat cable is used with a floppy converter there will either be no activity / lights or
what will be exhibited is two red lights on the Panel when running diagnostics, much like if you have no floppy or bad floppy hooked up.

If your floppy drive comes with a cable, and you have a cable which came with the converter and are confused which to use,  you should always use the one that came with the floppy converter.

Additional update-  The converters are no longer available for sale.

If you purchase a JM-215A I can provide modification instructions.

I may just post the instructions and a picture here…..