Yamaha Floppy Drive Repair

Does anyone have any resources for repairing a Yamaha DX7II floppy drive? The model number is Matsushita DDF3-1. It isn’t reading or writing discs and the discs aren’t seating properly. Tips on locating a new belt or info on the belt size would be great.

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Thought about trying this solution instead?

N-Drive 100 emulator for Yamaha DX7 II FD | USB floppy emulator Nalbantov N-Drive (floppyusbemulator.com)

Yes. That’s plan B. What’s your experience with an emulator?

They’re great - specifically the one’s a linked to - they make distinct adaptations to the drives used for the models. Some floppy drives were made to a specific purpose (ie YAMAHA Electone EL70 EL90) where drives were non-standard … hence a PC floppy drive will not work in its place.
Each drive comes with a pre-formatted memory stick representing 99 floppies, software to manipulate and copy floppy content to the USB stick and very concise installation instructions.
I done about 8 … 10 so far …

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Thanks for the info! How does it fit? Any rigging required to get it to seat properly? Any alterations to the synth case needed?

I can highly recommend the floppy emulator solution.
IF you have an internal or external floppy drive for your mac or pc. So you can put your physical floppies into the usb emulators memory stick. I looked for one that has both a text display for getting the right folder to load, I also recommend the emulators that have both buttons and a potentiometer , ( a knob that allows quick scrolling to folders and file).
Remember floppy drives 3.5 inch hard plastic discs came in 2 formats 720k and 1.44meg. The 1.44 drives can read the 720k discs but not the other way.
Years ago disc read errors were usually caused by dirty disk magnetic heads. I dont know if you can find a floppy disc cleaner nowadays but if you do put some isopropyl alcohol on the abrasive disc and run it a few times. If as you say the belt is stretched or bad, replacement is the only option. But again I recommend the emulator at between $ 50- $ 90 they save you from all the physical floppy disc woes.

Thanks for the info. I’m still curious as to whether the emulators fit into the floppy drive slot, or if you have to make alterations to the case.

The usb floppy emulator drives are physically the same size as regular floppy drives. I pulled up the service manual for the dx7iiFD and see there is a bracket that holds the drive in place and mounts with three screws.
The FD floppy drive is a DD or double density indicating a 720k drive. The HD floppy drives were for the 1.4 meg discs. There is some confusion on the as I noticed the note on some Yamaha floppies as 1.2 meg which was a 5 1/4” floppy disc format. Anyway the interface cable is the 34 pin used by most floppy drives and emulators. It is connector CN1 on the dx7 iiFD main board. Pin out looks to be the standard so replacement should be simple. If you have difficulty finding a dx7 iiFD floppy drive should you choose to do that remember you can also look for Yamaha cx5/cx5 ii computer external 3.5” drives as they are the same if you remove the dive from the external housing, and they are contemporary devices dx7 and cx5.

Thanks for this info. I’ll definitely go the emulator route if repairing the floppy drive isn’t successful. Speaking of that…

I disassembled the drive and discovered what looks like a broken read/write head. I couldn’t find a pic of how it should look or a replacement part online. As you can see from the pics, the underside of the upper arm has a square opening with a couple of tiny copper strands protruding. The lower plate has a white plastic piece that is connected along the right edge. I can pry it up, but it won’t come off. Is it supposed to? It looks like a cartridge assembly that fell out of the upper arm square part, but it’s really stuck in there.

Photo 1: lower section with tweezers holding the white piece vertically
Photo 2: lower section from front/slightly left
Photo 3: underside of top arm
Photo 4: same

Any advice with this is appreciated!

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Not sure about the DX7, but when I did this for my Ensoniq SD-1 I had to use a computer with an internal floppy drive. Some formats are so peculiar that the program needs to be able to directly control the floppy disc in order to read it. An external USB drive does not work.

I have successfully used the Emulator solution for many Yamaha and other project repairs (over 70) so can totally endorse this option. Very similar experience to [wernersaurus] with some very specific Yamaha drives, but thankfully these are few and far between. Otherwise the drive is a Panasonic (Matsushita) and Sankyo produced the motors for these floppy drives for many years.and there are plenty of them still available on various marketplaces to be used directly or cannibalised for parts.

Thank you for these replies. One question I have about the USB emulators: I can see how you’d be able to store voices (patches) to the hard drive, but how would you load them into the synth in the first place? That is, they used to sell third-party floppy disks with voices that you would load (e.g. SSU), So is there a database of these somewhere that you can access? Is MIDI involved somehow?

You’d either have to find a database of such (there may be i haven’t looked) or image the old floppies and write that onto the emulated partitions on the usb stick/floppy emulator whatever