Mitsumi D359M3D PC drive modification

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By Gregory

Expert (93)

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01-03-2014, 21:07

Can sombody tell me if the modification that is shown in de picture can also work for a MSX:

http://www.pitsch.de/stuff/amiga/tepe/mitsumid359m3d.jpg

The drive is a Mitsumi D359M3D.
As far I understand:

1 Cut pin 12 of from it's trace and connect pin 10 to this trace (so the drive will be set as 'A' drive).
So the DS 0 from the connector (pin 10) goes to DS 1 on the drive (DS 1 is standard on PC drives).

2 Cut pin 34 from its trace and connect pin 2 with this trace.
(pin 34: Drive ready/ Disk changed and pin 2 (disk change detect).

3 Connect pin 34 with the /Ready pin of the IC.

I also have this type of drive but with a slightly different PCB layout and the IC that pin 34 connects to is different on my drive.

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By luppie

Paladin (800)

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01-03-2014, 21:30

It depends on what MSX model you want to adjust it to.

By Gregory

Expert (93)

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01-03-2014, 21:56

luppie wrote:

It depends on what MSX model you want to adjust it to.

Well I have a few computers that need a drive change.
A 8280, 8250 and 8235.
I would like to start withe the 8280 and the 8250.

By luppie

Paladin (800)

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01-03-2014, 22:07

For the 8280 & 8250, you dont need to modify the drive. Just modify the cable Big smile

By Gregory

Expert (93)

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01-03-2014, 22:15

So it's the same for driva A and B? Just a modified cable?

I'll get started right away Smile

By luppie

Paladin (800)

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01-03-2014, 22:12

I'm not sure if this also works for drive B, this is the cable for drive A

By Daemos

Paragon (1649)

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01-03-2014, 23:03

On NMS825x the floppy drives use drive select jumpers. A: should be set to DS0 and B: should be set to DS1. The cable then stays exactly the same.

By Gregory

Expert (93)

Gregory's picture

02-03-2014, 11:44

Daemos wrote:

On NMS825x the floppy drives use drive select jumpers. A: should be set to DS0 and B: should be set to DS1. The cable then stays exactly the same.

There aren't any jumpers on this drive, you have to cut a trace and then solder it to another pin.

I made the modified cable and the start up routine is just like the standard drive but I get a disk-offline when I give the "files" command.

Two remarks:

* pin 33 on the diskdrive isn't ground (the trace that connects to it goes off to the controller)

* pin 14 on the diskdrive isn't connected to anything, there is no trace on pin 14

By luppie

Paladin (800)

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02-03-2014, 14:04

You could try for drive A connecting:
MSX pin 16 to drive pin 10 (ME_A)
And MSX pin 10 to drive pin 12 (DS0)

For drive B:
MSX pin 12 to drive pin 12 (DS1)
And MSX pin 16 to drive pin 16 (ME_B)

By Gregory

Expert (93)

Gregory's picture

02-03-2014, 18:57

luppie wrote:

You could try for drive A connecting:
MSX pin 16 to drive pin 10 (ME_A)
And MSX pin 10 to drive pin 12 (DS0)

For drive B:
MSX pin 12 to drive pin 12 (DS1)
And MSX pin 16 to drive pin 16 (ME_B)

Just to know we are on the same page, wich pinout are you using.

http://pinouts.ru/Storage/InternalDisk_pinout.shtml

The first table, controller pinout or the
second table, floppy diskdrive pinout (shugart interface).

Don't really know what the difference is between the two.

By luppie

Paladin (800)

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02-03-2014, 19:53

MSX Pinout is the Shugart pinout.
The PC-Drive has the pinout of the top-table.

So the cable you need to make is a cable that connects the PC drive to the Shugart interface.

This is the pinout of the NMS8250 floppy connector:

I wasn't aware of the fact a NMS8250 also uses the RDY signal (pin 34) (so the cable of my first post wont work, because this cable is for MSX's that dont need the RDY signal)

I already tried to get the RDY signal on this drive to work, but with no luck (I blew up the drive trying) I know there are different revisions of this drive. Can you post a picture of the PCB of the drive, maybe I can look into it if I have the same revision.

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