Details of the adapter leads for a floppy would be useful ..and probably my first job.
Here are the construction details for the internal floppy adapter:
You will need 34 way and 26 way IDC headers and a 26 way ribbon cable of suitable length
Mount the 26 way IDC on one end of the ribbon cable as normal with the red wire going to pin 1.
Split the ribbon cable at the other end between wires 11 and 12. (red wire is pin 1)
The piece of ribbon with wires 12 to 26 should be inserted into the IDC header so that wire 12 makes contact with pin 18 and wire 26 makes contact with pin 32 leaving pins 33 & 34 at the end unconnected.
This connects the following pins:
wire 12 >> pin 18 !FDCDRC >> !Direction
wire 13 >> pin 19 GND
wire 14 >> pin 20 !STEP >> !STEP
wire 15 >> pin 21 GND
wire 16 >> pin 22 !WDATA >> !Write data
wire 17 >> pin 23 GND
wire 18 >> pin 24 !WGATE >> !Write enable
wire 19 >> pin 25 GND
wire 20 >> pin 26 !TRACK0 >> !Track 0
wire 21 >> pin 27 GND
wire 22 >> pin 28 !WPROTC >> !Write protect
wire 23 >> pin 29 GND
wire 24 >> pin 30 !RDDA >> !Read data
wire 25 >> pin 31 GND
wire 26 >> pin 32 !SIDE >> !Side select
Clamp the IDC as normal then remove the top of the IDC header to reveal the unconnected IDC pins.
Then connect each of the following wires to each IDC pin as follows:
wire 2 >> pin 8 !INDEX >> !Index
wire 4 >> pin 12 !FDSELA >> !Drive select B
wire 6 >> pin 34 !DSKCHG >> !Disk change
wire 8 >> pin 5 !READY >> GND (Ready is not a signal present on IBM type floppies but needs to be grounded to work)
wire 10 >> pin 16 !MONA >> !Motor on B
wire 11 >> pin 2 !LOWDNS >> !High density
The easiest way to make the above connections is to drape a wire over the required IDC pin then refit the top of the header and press it together by hand.
Remove the top again and repeat for the next wire. You may break the latches on the top with this continual removal but it can still be used to push the wires on the pins, after which it should be replaced by an intact one from another 34 way header.
Finally, the first four remaining unconnected wires (1,3,5 & 7) which are all +5v can be soldered together and connected to the +5v line of a floppy drive power connector (0v comes from the GND on pins on the 34 way connecter).
Note that this can only be used if the floppy drive is +5v only, many early drives used both +12v and +5v. In this case, the +5v lines should be insulated and a molex splitter used to split the supply to the hard drive.
Wire 9 (!NOTCH) is the status of the HD hole in the floppy. This is used by the BIOS to determine the size of floppy inserted and if you try to format a floppy of the wrong size you get an error "Parameters not supported by drive". Unfortunately standard floppy drives don't have this signal so you either have to ground it (for 1.44MB) or leave it floating (for 720K) which means you can't format one size of floppy although you can always read & write correctly formatted 720K & 1.44MB floppies irrespective of the state of this signal. The BIOS call that generates this error is not used by the formatter in DOS 3.3x so you can always format any size disk by booting to DOS 3.3x first. (Some T5200s with original floppy drives also generate this error when trying to format 1.44MB drives so that signal might not be available on some original floppy drives but they were supplied with DOS 3.3 so it didn't cause a problem at the time)
To avoid these problems, my patched BIOS versions for both the T5200 and T3200SX have removed the check of this status bit so they will format any floppy with any DOS version. (Obviously you can still only format a floppy according to it's capacity)
If you are running my patched BIOS, the state of Wire 9 doesn't matter, if you are not using my BIOS, then Wire 9 should be grounded or left floating depending on what size floppies you want to format most and then boot to DOS3.3 to format the other size (gnd = 1.44MB, float = 720K).
If grounding wire 9, connect it to another ground pin such as pin 7 although if you have a floppy drive with ground pins removed (see below), you will have to join it to the wire going to pin 5.
Warning: Some drives (e.g. more recent Mitsumi drives) don't have all the GND pins fitted on the 34 way socket. This means that the !READY signal might not make contact with GND if pin 5 is missing and the drive may not work. Pin 5 is present on the Mitsumi drives which is why that one is used but if other manufacturers did the same thing and didn't have pin 5 then you might have to move that wire to another pin or connect it directly to GND.
Also as there are fewer GND pins, there may be insufficient GND return for the +5V supply in which case the molex splitter should be used. I suggest avoiding this type of drive if you have a choice.
Here are some pics:
(Wire 9 is left floating in these pics but should probably be grounded as mentioned above)
Strictly speaking, grounding the !READY line is not an ideal solution as it is then grounded for all floppy drives connected to the bus, although doing it this way is a simple solution which doesn't require any soldering if you use a molex splitter for power. I don't think this will have any effect on the T5200 although it might cause problems if this cable is used on another system with other drives. It might also cause issues with the original Toshiba 5.25" external floppy drive if that made use of the !READY signal. (There won't be any problems with 3.5" external drives as they don't have the !READY signal anyway). In the unlikely event that this is an issue, it may be fixed as follows:
Remove wire 8 from pin 5 of the 34 way IDC and solder it to the unbanded end of a high current (1A or so) schottky diode and solder the other (banded) end of the diode to wire 10 (!MONA/!motor on B) while leaving that wire connected to both IDC connectors (normal diodes don't seem to work with all drives due to their voltage drop - maybe a more complex transistor circuit would be better). To do this means scraping away the insulation of wire 10 to expose the bare metal for soldering. This change makes the !READY signal follow the motor on signal.