I just received a Tandy 1200 HD and I could not get it to read a 360k disk with Dos 6.22 so I pulled the floppy drive out and noticed that the floppy cable has what seems to me to be an unusual modification. This is not the version that carries power to the drive over the floppy cable and has punched out wires on the cable (the 360k floppy drive has the typical power connector shown in the drive photo5).
With this cable, the colored wire (pin 1 wire) is connected to pin 1 on the floppy connector but is cut and does not connect to the connector that plugs into the motherboard (photos 1 and 2 below). Instead, the cable is inserted into the motherboard connector with the second wire attached to pin 1 of the connector. As a result, all of the wires are offset by one at the motherboard connector (wire 3 connects to pin 2, wire 4 to pin 3, wire 34 to pin 33 and no wire connected to pin 34 etc.). I tried to show this on the Cable diagram photo.
At first I thought the cable was made up incorrectly but after more testing I found that the drive works fine with this cable, it just won't read my Dos 6.22 disk. During my testing I connected the floppy drive to my 386 test computer with a normal floppy cable and the drive works fine so it seems like the drive uses standard connections but the motherboard connector is not standard and requires this modified cable.
I looked for information on this type of cable modification but haven't seen anything so I'm wondering if anyone knows why Tandy would have made this modification.
If this is something that everyone knows about but me, I apologize for wasting your time.
Thanks!
With this cable, the colored wire (pin 1 wire) is connected to pin 1 on the floppy connector but is cut and does not connect to the connector that plugs into the motherboard (photos 1 and 2 below). Instead, the cable is inserted into the motherboard connector with the second wire attached to pin 1 of the connector. As a result, all of the wires are offset by one at the motherboard connector (wire 3 connects to pin 2, wire 4 to pin 3, wire 34 to pin 33 and no wire connected to pin 34 etc.). I tried to show this on the Cable diagram photo.
At first I thought the cable was made up incorrectly but after more testing I found that the drive works fine with this cable, it just won't read my Dos 6.22 disk. During my testing I connected the floppy drive to my 386 test computer with a normal floppy cable and the drive works fine so it seems like the drive uses standard connections but the motherboard connector is not standard and requires this modified cable.
I looked for information on this type of cable modification but haven't seen anything so I'm wondering if anyone knows why Tandy would have made this modification.
If this is something that everyone knows about but me, I apologize for wasting your time.
Thanks!
