Originally Posted by
jmullett
I don't know the Mark 9 control but mine has a circa 1992 Mark 11 control with a NEC PC9801-UV that uses a Japanese version of DOS the disks are 720K and can be read in a regular PC with a floppy controller and drive. I also have had luck using a Sabrent USB floppy drive as well on a newer computer without the floppy controller. Never had too much problem with the NEC PC except the drives. I actually paid a guy to rebuild a pair for me a couple of years ago here in the USA.
I encourage you to make an image of the floppy for back-up purposes as they do tend to get corrupt over time. You can cover the notch on one side of the 1.44 MB floppy with a piece of electrical tape or part of a disk label to convert/trick the computer into thinking it is a 720 k disk. I haven't found anybody who can convert the floppies to USB drive emulator. Many people say their product can, but as soon as they found out it is a NEC FD1135D drive they admit they cannot. I've heard that there is a guy in Poland named Lotharek who makes a VFO board daughter board for the HXC floppy emulators that supposedly work but he doesn't get back to me.
I think you first need to get that computer to boot up, and then I'd say you need to check all your power supplies making sure they all working properly. The TTL chips in these machines require the proper logic level voltage and have little tolerance for error. I've replaced a few of my power supplies over the years. There are maybe 8 of them inside the controller behind the paper tape drive in the lower front part of the cabinet.