SONY 920 floppy mod for keyboard

Hello everyone. I have problems trying to make a SONY MPF920 z/161 work on an Ensoniq EPS 16+, not to say its driving me crazy

I know maybe its a little offtopic, but I appeal to you beacuse your wide knowledge modding these drives.

The original floppy is a Panasonic JU257a/303p. It has headers problems.
ANyway, supposedly I have to turn the SONY to SHUGART interface.
So first I turned it to DS0 by changing the 0ohm resistor.

Then cutted the 34 pin trace, and connected what previously went to pin34 to pin2 (change disk)

Then I have to link ''ready'' signal to pin34. Im not sure where to find it, but based on some images from this forum, I took it from pin 14 of BA6986FS chip.

So it starts working on the keyboard. Led blinking. The keyboard asks for operative system at first. Insert OS disk, load perfectly. I take it out.

I put a sound library diskete. Press LOAD button, it loads it and here comes the problem. Once it has loaded the sound library, each time I try to navigate, the FDD load at 0 again the disk. If i want to load the only sound it allows to show, it says ''disk drive not ready''.

With the original FDD, once the sound library is loaded, you can navigate the diskette info as the fdd stays quiet. It doesnt read any time. ANd of course it load the instruments.

So I checked voltage on the ribbon cable pin 2, and with the SONY each time I press navigate buttons it sends 0 volts, while with Panasonic it stays at 5volts. So I think the sony is like detecting a change disk constantly or something like that.

I dont know how exactly ''ready'' and ''change disk' signals work.

I think the SONY fdd behaves like there's no disk on, even tough it reads it at first. ''DIsk drive not ready'' message shows when theres no disk inside the drive
Here's a pic how i Have it right now:


Please don't tell me to put a floppy emulator. I know about that, but I really want to make this work
Any help will be really appreciated!

PD: If it serves for something the floppy controller inside the keyboard is a VL1772-02 pc

I wanted to say that I also have a NEC FD1231H AND NEC FD1148 from 1995 and 1996, if someone knows how to mod them

[lesta_smsc]

May or may not help but some info about conversion of the Sony disk on this site. Seems like it might not be a simple conversion with the revision of the drive you have:

http://sounddoctorin.com/synthtec/floppyhelp.htm

http://floppy.shugart.free.fr/page.p...r-10/index.htm - use Chrome to translate to English

http://obligement.free.fr/articles/r..._disquette.php - use Chrome to translate to English

[supaduper]

Move the 0ohm back to j31, some sony MPF 920 need to be on that to work

Originally Posted by supaduper

Move the 0ohm back to j31, some sony MPF 920 need to be on that to work

If I do that I set it back to ds1 and it doesn't work. Both jc31 and jc30 go to the same trace/ pin of BH9558kv chip, it only changes pin10 or 12 from the cable

Finally I got ittt!!!
I've searched about the Floppy Controller the VL1772-02 pc, and its the same in the Atari st so I searched floppy mods for the Atari. The fact is all about ''change disk''. Even when both Panasonic and Sony switches are ''normal open'', in the SONY they work inverted, in the logic board I think. So when I took the change disk signal from the density select switch and putted a high density diskette (hole oppened) it finally worked fine.

So all this time the switch CT IN (with amiga mod) was telling the system the floppy was empty when a diskette was inside, and thats why it load each time from 0.
All this time all I had to do was this
https://tonnemansblog.wordpress.com/...aTmve4MMuRNCTw

So it can be fixed with the inverter or maybe getting some normal closed switch that fit on the floppy drive.

I will update the news tomorrow. Thanks to lesta_smsc and supaduper for trying to help me

[lesta_smsc]

Glad you got it sorted... BTW that is demonstrated in the table on the link I sent lol.

Now I have it working. It reads and write, but it can't format... Someone had problem like this with Amiga??