What I have: A brand new board revision C (good quality Lotharek!) and latest firmware. The keyboard uses standard 2DD disks with midi files on it.
Emulator works fine on PC.
Replaced the internal TEAC FD 235F-5482-U in the keyboard with the emulator and a straight cable. The TEAC was jumpered to pin34= Ready, pin2 = disc change, and DS0. Looks pretty shugart standard to me. So I selected the generic shugart mode on the emulator. I had to jumper the emulator to ID3 = MTRON otherwise the access from the keyboard could not be recognized.
I have created a lot of HEF files (actually all the Desktop software alows), but cannot read them on the keyboard. On some files, the keyboard suggests reformatting, which worked so far on files with mfm and 300 rpm. I can then write to the disks recording on the keyboard, one can see and hear the keyboard writing and reading. After a reboot, everything is gone.
This model of the FD235 can be rejumpered from Shugart to PC pinout,
so I connected the original TEAC to my PC and dumped original Yamaha disks to the SD card - unreadable by the keyboard.
On the other hand, the mfm 300 files formatted on the keyboard are unreadable on the PC (Win 7 / 64 bit). I tried different SD cards - same effect.
In the past, I could interchange midi disks between keyboard and PC on 2DD disks.
There are reports that the internal drive of the keyboard could easily be exchanged to a PC interface drive: http://cowo.supersized.org/archives/24- ... drive.html
So it should work. I assume the problem is either in front of the PC, or in front of the keyboard.

Any ideas? Your help is appreciated.
oscar