Mitsumi D359M3D PC drive modification

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By Hans41

Resident (37)

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10-09-2017, 22:12

Gregory,

Do you maybe have unmodified drives lying around, cause the cable trick with two drives (default to ds1) is really easy ?

By Philip

Master (183)

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10-09-2017, 22:27

Perhaps it's a ready signal issue ? You can try to connect pin 34 on the mainboard to gnd.

By Gregory

Expert (74)

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11-09-2017, 03:36

Yes, I still have some unmodified drives, can you give a bit more information about the cable modification?

By Gregory

Expert (74)

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11-09-2017, 03:37

yes, i have some unmodified drives, can you give a bit more info about this cable trick?

By Hans41

Resident (37)

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11-09-2017, 09:35

Gregory,

You will sacrifice two flat cables. LOL!

The only thing you have to do:

Drive A: cut lines 10 and 12 of the cable, connect line 10 from the controller/motherboard to line 12 (to the drive).
That makes the signal for ds0 connected to the ds1 connection of the floppy drive. Line 12 from the controller/motherboard will become unused.

Plus,connect one of the uneven lines (33 for example) to line 34 (going to the drive). That gives a disk ready signal to the drive. Well, not really, but the drive thinks it gets a ready signal. All uneven lines contain a ground signal.

Drive B: the only thing you have to do, is to get a disk ready signal to the drive. The drive by default already is ds1(B-drive) Easy to do, same as with the a-drive. Just cut lines 33 and 34. Connect line 33 from motherboard/controller to 34 (to the drive) and your second drive thinks it has a disk ready signal.

I've done this on one of my 8280's and it works flawlessly. Basically, I followed Luppie's instructions. Big smile

By Gregory

Expert (74)

Gregory's picture

11-09-2017, 16:12

Hans41 wrote:

Gregory,

You will sacrifice two flat cables. LOL!

The only thing you have to do:

Drive A: cut lines 10 and 12 of the cable, connect line 10 from the controller/motherboard to line 12 (to the drive).
That makes the signal for ds0 connected to the ds1 connection of the floppy drive. Line 12 from the controller/motherboard will become unused.

Plus,connect one of the uneven lines (33 for example) to line 34 (going to the drive). That gives a disk ready signal to the drive. Well, not really, but the drive thinks it gets a ready signal. All uneven lines contain a ground signal.

Drive B: the only thing you have to do, is to get a disk ready signal to the drive. The drive by default already is ds1(B-drive) Easy to do, same as with the a-drive. Just cut lines 33 and 34. Connect line 33 from motherboard/controller to 34 (to the drive) and your second drive thinks it has a disk ready signal.

I've done this on one of my 8280's and it works flawlessly. Basically, I followed Luppie's instructions. Big smile

OK, thanks for the explanation. I'll try to find the necessary components and give it at try. Thanx.

By Gregory

Expert (74)

Gregory's picture

13-09-2017, 17:50

I tried the cable hack today. I double checked the wiring of the cable.
But I get a disk offline on both drives.
On start up the leds of the drives light up as they should and 'files "a:'' and files "b:" adresses the correct drives but I get a disk offline. Can you tell me what the brand and type is of the drives you used in the 8280?

By Hans41

Resident (37)

Hans41's picture

13-09-2017, 19:00

Hi Gregory,

That's a shame. You did connect ground to pins 34 on both drives ?

BTW, I'm not sure if it's necessary, but I have the line that I used to get ground signal of still (also) connected through. What I mean by that, is that if you take line 33, I have it connected to 33 and 34 (to the drive).

Sorry to ask, but you tried everything, also 'call format',etc. ?

I used Mitsumi D359M3 drives without modifications.

By Hans41

Resident (37)

Hans41's picture

13-09-2017, 18:52

BTW, what kind of disks do you use ? HD or DD ?

By Philip

Master (183)

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13-09-2017, 23:56

The diskdrive does not care about the ready signal, only the computer expects a ready signal.
If you connect pin 33 & 34 on one of the floppy connectors on the motherboard the computer thinks the drive is always ready and it will be happy Smile
See also here:
https://www.msx.org/wiki/MSX_FAQ#Can_I_install_a_PC_diskdriv...

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