Am 06.05.2013 08:17 schrieb Peter Dassow:
But this is almost unbelievable that nobody yet created a logic board with an FPGA/whatever which converts the signals/creates the missing signals. May be too much old drives are still available ...
You don't need a FPGA, the circuit is rather simple. This is the schematic diagram of an Ehring FDC4 http://www.harrowalsh.de/Elektronik/APPLEBOX/Images/FDC4Schaltplan.jpgand the conversion logic is the part on the right, between the 20pin and 34pin connector
Regards Patrick