i fitted go-tek emulators to mz 2000 and ctk 811ex ,even with the usb memory stick formatted, the units did not work,they lit up alright but to transfer data no go.ken
can you format them on a computer? if no ,look at the disc face ,make shore the left hand hole is closed, it's the same for both disc size 720 mb . 1.44 mb ,I hope this is of help to you.ken