before I start modifying the HxC, can you confirm that the internal wiring of the Cased SD HxC will support DS3 and that the firmware will recognise the 4th drive please?
I have not found a schematicv for the SD version, only the USB one, and the USB schematic certainly suggests that the USB version would support DS3.
Can you confirm that either the schematic is wrong, or that there is a difference between the USB version and the SD version in this regard. I think this may be the case as the USB version seems to be only for a PC - and modern PCs only supports two floppies anyway.
What do you mean by the "four switches of the virtual drive should be off"?
Are you talking about the ID jumpers on the HxC?
If I want to use DS2 and DS3, then I need DS2 pinned on the jumper block as well as the wire grounding Line 6 on the DS3 jumper block
The schematic is there :http://hxc2001.com/download/floppy_driv ... or_Kit.zip
With your system DS3 = Wire 6. So you have to connect this wire to one hxc drive select (after the jumper block).
In fact with the rev c you have just to make a bridge between the wire 6 and one row of the jumper block.
Please have a look to the schematic.