Replace a Panasonic FS-A1F Diskdrive with a PC Drive

Instruction designed and written by Erik Luppes (luppie), original here, reproduction kindly permitted by Erik.

This instruction shows how to connect a Samsung SFD-321B FDD to a Panasonic FS-A1F.

On the Internet I found a couple of instructions on howto connect a PC drive to a Panasonic MSX. In my opinion these instructions are too complex and/or not 100% compatible with the original diskdrive.

This instruction works with older revisions of the Samsung SFD-321B.
Please make sure that the Samsung SFD-321B you use has a HD sensor (the newest revision of this drive does not have this sensor, causing no support for formatting 720kb DD disks)

To minimize the damage to the mainbord I chose to make a small convertor on a small prototype PCB.

On the small PCB the following connections are made:

Signal	26 pin MSX	34 pin FDD
GND	01	Power Connector
RDY	02	34
+5V	03	Power Connector
Index	04	08
Drive Select 0	06	10
Motor ON	08	16
Side Select	10	32
Direction Select	14	18
Step	16	20
Write Data	18	22
Write Gate	20	24
Track 00	22	26
Write Protect	24	28
Read Data	26	30

To make the Samsung SFD-321B 100% compatible the following modifications need te be made.

Replace jumper DS1 to DS0 (To make it the A drive)
Replace jumper DC to RDY (To put the RDY signal on pin 34)
Put a jumper on OPA (this adds 720kb support)

Since the diskdrive has a HD Disk sensor, you need to put a piece of tape on the HD hole. To overcome this, it is possible to remove the HD sensor.

Now you’ve got a 100% compatible diskdrive, without modifications to your mainboard.