QX5FD, QX3: Floppy replacement & USB emulators

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EX5_etc
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QX5FD, QX3: Floppy replacement & USB emulators

Unread post by EX5_etc » Sun Aug 31, 2014 9:03 am

Hi folks.

Over the years, as you may recall, I have started a few threads about replacements of floppy drives for older Yamaha midi equipment. The last of the devices I own that did not have any such modification done to it was the QX5FD, my first sequencer that still goes strong and so does its floppy drive. Recently the sequencer joined the group of devices that feature a USB emulator and this is its story.

According to the service manuals, the QX5FD (introduced in 1988) and the QX3 (introduced in 1987) share the same design as far as the floppy drive goes. The common layout consists of a Western Digital WD1772PH-02 floppy controller and a Toshiba ND-352S-A (FDD4268G0K, LR56034) drive. Thus, the modification I did for the QX5FD should work for the QX3 as well, but I don't have one to test it out. "Should" is the magic word here. I have seen online posts claiming that Yamaha used both Toshiba and Mitsubishi drives in those devices. Who knows... An internet search revealed that some Electone keyboards (such as the EL-90) also use the same drive but a different controller. So this adapter may have more applications but it's up to the individual user to check it out.

I faced two problems when I started working on this project; both were due to serious mistakes made by Yamaha engineers at the time of product design. The first is that the service manual is wrong and the second that they have switched the ribbon cable connector. Both issues are shown corrected in the attached pictures.

The original 34-pin ND-352S-A floppy drive looks very similar to more modern 34-pin drives but the similarities end there. For whatever reason the pinouts are not the same. Pin 1 of a modern drive is pin 34 for the Toshiba drive, pin 2 is 33, ..., pin 33 is 2, and pin 34 is 1. Then the /DISKC, /SIDE and /READY signals are shown as DISKC, SIDE and READY in the schematics. I won't go into details as to how I wasted a lot of time working things out. I will only say that for the /READY signal I used the same trick as I did for the SY85 floppy adapter.

One thing I noticed is that my adapter for the QX5FD does NOT work 100% with the Sony MPF920. It always quits in the middle of a "Disk Copy" process and a power cycling is the only remedy. In other words a disk cannot be duplicated. Not much I can do or care to do about this. The adapter also fails the "Disk Copy" process with the SFRM72-TU100K floppy emulator (the only jumper on it must be set to S1). That emulator worked flawlessly with my SY99 and its only drawback was that it required the use of software that run on WinXP only. With the exception of "Disk Copy" all other functions appear to work well either with a Sony MPF920 drive or the SFRM72-TU100K emulator.

There is salvation however. Instead of the SFRM72-TU100K I used the SFRM72-FU-DL emulator, the same one I now have installed on my SY99. A detailed description of the additional modifications I did on that emulator can be found here:

http://www.yamahaforums.co.uk/forum/vie ... =55&t=7440

For the QX5FD I chose to repeat only the modification that disconnects the USB stick without removing it from the emulator when a disk must be changed. Thus, I won't repeat here what the red switch does. The only jumper on the SFRM72-FU-DL emulator must be set to S1, if my adapter is to be used. For details please read the SY99 thread above.

One of the attached pictures shows the adapter I made for the QX5FD. The socket in the middle carried a four-NAND-gate IC (in a four-NOT-gate configuration) that is not used now. It helped me realize that the DISKC, SIDE and READY signals were already inverted and thus my inverters had no place there. So I removed them. Of course if Yamaha had printed the service manual correctly I would not have used that socket in my adapter in the first place.

So, why is the SFRM72-FU-DL better than the SFRM72-TU100K? Because it requires no special software to format the USB stick into 999 virtual disks (or to read them) and because it offers the disk duplication option in its firmware. The first issue is explained if you click on the link above. The second is a simple action even though it takes a few more steps than using a regular floppy drive.

To save data to a virtual disk:

- Use the "save" command on the QX5FD to save your data/files on the flash memory of the emulator
- Remove the stick or press the red button if you have one
- Use the two small buttons to select a folder (virtual disk)
- Insert a USB stick or depress the red button if you have one
- Press the left button once; "d2" appears on the screen and the flash memory is copied to the selected folder on the stick

To load data from a virtual disk:

- Remove the stick or press the red button if you have one
- Use the two small buttons to select a folder (virtual disk)
- Insert a USB stick or depress the red button if you have one
- Press the right button once; "d0" appears on the screen and the selected folder on the stick is copied to the flash memory
- Use the "load" command on the QX5FD to load your data/files to the sequencer

To duplicate a virtual disk:

- Remove the stick or press the red button if you have one.
- Use the two small buttons to select a folder (virtual disk), the "original" one that will be duplicated
- Insert a USB stick or depress the red button if you have one
- Press the right button once; "d0" appears on the screen and the selected folder on the stick is copied to the flash memory
- Remove the stick or press the red button if you have one.
- Use the two small buttons to select a different folder (virtual disk), the "duplicate" one
- Insert the same USB stick or depress the red button if you have one
- Press the left button once; "d2" appears on the screen and the flash memory is copied to the selected folder on the stick
- That's it, the "disk" has been duplicated in one operation instead of inserting and ejecting floppies as in the original drive.

One important detail to remember when working with the SFRM72-FU-DL emulator: any load/save operation in your synth or sequencer takes place in the flash memory of the emulator. That flash must be transferred on the stick when you are done. The manufacturer claims that it retains its contents after power down but I did not see this happen with my QX5FD. Every time I powered on I had to load the data using the load process described above because the flash memory had erased itself.

The attached pictures show: 1) the pinout table of the adapter, 2) the switched pinout implemented by Yamaha, 3) the QX5FD on the operation table with the original grey emulator, 4) the prototype of the adapter I made, 5) the modification of the emulator, 6) the required foldings of the foot-long ribbon cable to make it fit inside the sequencer, and 7) the painted emulator installed and working.

If anyone has a way to fix the "Disk Copy" function that fails with a Sony floppy drive, please feel free to contribute your findings.

That's all. At this point I have taken my QX5FD from the 20th century to the 21st one and that is all I wanted to do in the first place. Thus, the emulator upgrade story that I started back in January of 2011 on the ex5tech.com site, ends for me as I have no other devices to upgrade.

DrF
Attachments
qx5fd1.jpg
Adapter pinout table
qx5fd2.jpg
Switched pinouts
qx5fd3.jpg
QX5FD undergoing surgery
qx5fd4.jpg
One more of my prototype adapters
qx5fd5.jpg
The emulator modified to stop required ejections
qx5fd6.jpg
Folding the long ribbon cable carefully
qx5fd7.jpg
A happy QX5FD with USB emulator and blue LCD
Motif XF6, DeepMind 12D, MicroArranger, MicroKorg S, SY99, SY85, QS300, PSR1000, WX5, EX5R, A5000, TG500, TG55, RM50, QY700, QY100, QX5FD, MDF3, MJC8, EMX2, YDP2006, REV500, EMP700, EQ500U, MCS2, AW16G, Axiom Pro 49, AKAI Pro Advance 49, Arturia KeyLab mkII 61, and a few other things by Behringer, Evolution, Philips, Tascam, Technical Pro, Yamaha, etc, etc,... I wish I had time to use all this stuff; I am not even pro. :-)
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