Thanks for your message.
Yes it is strange that the 5 volts is not taken from the PSU.
I am not too bothered about the disc for the moment as my PC interface works very well even at 300 Baud using MFI.
I don't find the slow speed much of a problem.
My other CNC Lathe (Conect Cadet Plus) is 9600 Baud but it is software driven (DOS) running in DosBox on windows10.
I will keep looking for information about the FDD it will eventually turn up somewhere.
I have only had the C5 for a month and nothing worked properly when I got it.
Now everything except the FDD works so I am happy with that.