Loading MSX DX7 Editor using MicroWaver WAV File

Recently I acquired a used MSX Yamaha YIS503II Home Personal Computer with several cartridges and a YK-20 keyboard. I posted an earlier article about the find. One thing that was missing with the package was the Yamaha DX7 MSX Editor, specifically the YRM-103 DX7 Voicing Program. My system also did not come with the MSX Floppy Drive system, however it did have the ability to transfer data using cassette tape. I did some research and discovered that it was possible to acquire the Yamaha cartridges in ROM format. I then found out it was possible to convert those ROM files to WAV format using a program called MicroWaver. I also used another that worked called Caslink2, however MicroWaver was the only program I could successfully convert to a higher bps rate that actually worked. A higher bps rate means a faster rate of transfer.

In the video you’ll see that on my MacBook Air I have a YRM-103 DX7 WAV file opened in Audacity. On my MSX computer I typed the command BLOAD”CAS:”,R and hit enter. I then played back the WAV file. You’ll notice that the MSX responds with LOADING and after about 15 seconds it loads up the YRM-103 DX7 Voicing Program beautifully. My MSX YAMAHA YIS50II has both the SFG-05 FM Sound Synthesizer Unit II module installed which includes both audio and MIDI in/out ports. I successfully was able to connect my Yamaha DX-7 and both edit and transfer data. Cool!

I now have one last potentially major problem to solve. I desperately want to use the DMS1 Mk2 MIDI Recorder for SFG-05 and do have the ROM file for it. However, when I convert it to WAV format it will get recognized and transfer appropriately with my setup, BUT my MSX then reboots at the end of the process. This reboot effectively clears the RAM memory and leaves me with an OK prompt. There is no start command for the DMS1 mk2 program so something either in the original ROM file or something I’m doing incorrect is causing it to not load. I’ve doing a couple of days of intensive testing and research and have come to the following conclusion. The ROM files were intended for Emulator use primarily and not for the use of REAL MSX machines. What I’m doing is out of the ordinary and perhaps not possible. I would love to have the DMS1 mk2 sequencer program working to create some of those old school 80’s tracks. I’m just not sure why the MSX is rebooting on it’s own. I used the blueMSX Emulator and the DMS1 ROM file worked great.

I also noticed that ROM files that contain a “Part 1” and “Part 2”, which is what I presume are two disks, don’t transfer well if at all via WAV format. The MSX Computer recognizes both parts, will load them, however the MSX computer YIS503II will ALWAYS reset or reboot after transfer completion. Again this results in memory being cleared and thus the program is gone. There is something about transferring multiple disks or parts that does not work via the PC WAV method so far. If I have a file with only one disk or part, it works great as with the YRM-103 DX7 ROM file above. It’s only one part and thus loads fine. If I can get the DMS1 to load than I would be set being able to work with the built in 4-OP SFG-05 and the Yamaha DX-7. That would be pretty cool and quite retro considering all of this is 1983-1986 stuff.

I’ll update this article in the comments section as I do more testing and discover more info.

Yamaha YIS503II MSX1 with SFG-05
Yamaha YIS503II MSX1 with SFG-05

13 thoughts on “Loading MSX DX7 Editor using MicroWaver WAV File

  1. Here is more info about my current issue.

    I have a DMS1.rom file that I can convert with MicroWAVeRunner or CASlink2 to WAV no problem. When I playback the file and try to BLOAD”CAS:”,R load on my MSX machine it loads both part 1 and part 2 files but then reboots upon completion. This clears the memory and we’re back at square one.

    So, I then try a work around. I use a program called MSXR2B which is a .rom to .bin converter program for MSX files. I convert the DMS1.rom which outputs to two files, DMS11.bin and DMS12.bin. I now then convert these to WAV format using MicroWAVeRunner and get two WAV output files. I try to load these to the MSX machine using BLOAD”CAS:”,R:BLOAD”CAS:”,R command but this time the after everything loads the MSX hangs. If I just try the one command BLOAD”CAS:”,R it still loads and hangs. It seems closer, but still no luck.

    Again, the problem is that I cannot find a way to properly transfer and load multiple cassette WAV files into a real MSX CX5M type of machine. It either hangs or reboots. I have tried different bps, speeds, and volume levels, but none seem to work or get me any closer.

    Thus, my conclusion thus far is that multiple files cannot be transferred to a real MSX, but rather are solely intended for Emulator use. Or, I am doing something wrong, often can be the case….ala user error!

    I’ll update further as I discover new info. Thanks!

    1. If there’s two files, probably you can concatenate them together. Though most ROMs I have are a single file? I know of three places where you can find CX5M ROM files, and very often they differ slightly so it might be worth trying out different versions of the same ROM:


      The MegaFlashROM SCC+ SD that I mentioned before (http://msxcartridgeshop.com/) is of great utility but does cost a few bucks, it’s true. There are cheaper alternatives such as ericb’s flash cartridges (http://msx.ebsoft.fr/MAB-Flash.php), but in your case because you don’t have a disk drive, I don’t know if there will be a way for you to get the software onto the cartridge.

      The reason why you need these flash cartridges is that the software was originally made for ROM cartridges, and it uses the system’s internal RAM memory for its data. If you load the software in RAM in stead, sometimes it works, but other times it will cause problems because things start to overwrite each other…

      By the way, if your goal is to play the internal sound chip through MIDI (so, to have it act as a slave to other MIDI equipment), have you tried the internal software? Type CALL MUSIC in Basic to run it. To edit the sounds, you need the YRM-502 FM Voicing Program II, I don’t know if that works with your WAVer loading method…

      1. Thank you for the info. My research combined with some of your info as helped me to determine that the problem seems to be RAM and Cartridge related. The data loads into the RAM area correctly, but then code embedded in the ROM likely directs the machine to then “looks for” the data on a cartridge, thus clearing the RAM. Since I am using WAV transfer and not a cartridge, it stands to be likely that that I’ll need a cartridge in the slot for all of this to work. Thus it’s looking like the MegaFlashROM SCC+ SD will be necessary.

        Also, I am familiar with the CALL MUSIC command and it works very well. I also do have the YRM-502 FM Voicing cartridge as well. My only real issue so far has been to get a decent sequencer running on the YIS503. The DMS1 mk2 seems to have everything I require, however that likely will require the flash cartridge mentioned above.

        If correct, the SFG-05 FM module that I have underneath the YIS503II is exactly the same as the Yamaha FB-01. I read both have the same internals. I also have the Yamaha FB-01 and the difference I notice is that the FB-01 is much noisier. The SFG-05 is noticeably quieter which is nice. Neither rivals my Yamaha DX7 or TX gear, BUT with a properly working MSX sequencer, the YIS50II could be a valuable composition tool for me and that’s my goal thus far to get a sequencer in there.

        Thanks again for the information. I great appreciate your time and hopefully I’ll be able to work out the kinks in the system very soon.

      2. I recently picked up a CX-5M and was looking at collecting all the YRM cartridges, but this looks like a much better was to go. So if I’m reading this correct I can put all the YRM ROM files onto a MicroSD card all just CALL them up as needed with this device plugged it? Also, does the 512k version add 512k to the system or is that just ROM only memory?


  2. After another day of research I’ve come to the conclusion that pretty much nobody uses the MSX Home computer for making music, rather they use it purely for gaming. I’ve tried just about everything and it seems one is out of luck with using real hardware MSX computers if yo want to do any sort of music.

    My goal was basically the following:

    1. I wanted to be able to connect the Yamaha YIS503II MSX1 to my Yamaha DX7 and edit the voices. This I have successfully been able to achieve by transferring the WAV file YRM-103 DX7 voice editor to my MSX machine. This works great.

    2. Now that I have both the SFG-05 and the DX7 connected and working it only makes sense to want to sequence those instruments to create an old school 80’s groove. Well it seems the ONLY way to really achieve this using just the hardware MSX1 is to use the DMS-II Real Time Sequencer by By Abdul H. Ibrahim. This is where the major problem occurs. This cartridge is no longer available and the only known ROM available doesn’t work on a real MSX1 machine. You have to use emulation such as blueMSX.

    All this means is that I can pretty much chuck my Yamaha YIS503II MSX1 out the window. Yes, it’s pretty much a worthless machine if you can’t get it to do the basics. Of course I could just use it to program my DX7, but it probably would be easier with MidiQuest or another software editor. Since the DMS-II sequencer is restricted to the emulators only you are pretty much stuck with the computer already. One work around might be to use the YRM55 FM Music Computer II cartridge I have but that is strictly a notation sequencer. It works well but the DMS-II would have been more practical.

    Ultimately, this beautiful looking retro YIS503II MSX1 home computer has been a real bust. You can’t win them all! With no way to get the existing roms to load, no access to cartridges, and most importantly, zero users around the web doing this I find it’s becoming pretty pointless to continue with any sort of MSX music. Note that I’ve tried using the emulators such as blueMSX and It’s painfully slow to do anything useful.

    Pretty much with the MSX platform these days it’s all about the games and not the music. At this point I wouldn’t recommend acquiring any sort of MSX home computer for music creation or editing. There’s just no interest in it at all. My hope was to have the DX7 voice editor working along with the sequencer to compose some tracks and show that the MSX1 could be a fun retro 80’s music machine. Unfortunately, this beautiful MSX1 machine now lives on a shelf in my studio. It just doesn’t work with music and I think everyone already knew that….laugh.

    1. Hi Jim,

      Whenever you don’t succeed in finding something, you should still avoid the term “nowhere available”. I know there’s still some DMS stuff in my old stock, including the DMS-II Sequencer cartridges. Do you want me to look for them?
      I’m afraid it’s too late now send you a list with the old stock of Yamaha MSX music software I dug out of storage a couple of years ago and you might have had fun with. Pretty much all of it is sold now, except YRM-103, 104, 305 and 501.


  3. Laurens Holst on Youtube replied with the following info that might just yet allow me to get the DMS sequencer running on my MSX1. It does mean I’ll have to snag a custom cartridge though which seems to cost a bit. We’ll see.

    Originally it is an actual cartridge, however I don’t own it so in stead I loaded a ROM file into that MegaFlashROM cartridge. It’s playing on an actual CX5MII computer :). I don’t know why it doesn’t work when loaded via WAVer…

    I don’t have a disk drive either, but the MegaFlashROM SCC+ SD 512K (sold here: http://msxcartridgeshop.com/) has an SD card drive so you can easily transfer files from PC to MSX. It’s really quite a neat all-purpose cartridge, it has so many useful functions, if you’re willing to spend some money I can recommend getting it.

    Here’s a video of Laurens Holst working with the DMS sequencer on his CX5MII computer.

  4. I’m finally getting closer to my answer:

    It appears now that the DMS2 sequencer needs a CX5MII (or any MSX(2) with memory mapper I guess) and the SFG-05 sound module.

    The Yamaha YIS503II is strictly an MSX1 version.

    The Yamaha YIS503III is the MSX2 version.

    So it appears, the DMS2 sequencer will not run on an MSX1 computer. I also noticed there is no memory mapper on the YIS503II which is also required. The YIS503II does however have the SFG-05 module installed, but in my case the SFG-01 module would have been better. I then could have at least loaded the DMS1 sequencer which is the old one. It seems the YIS503II is sort of a half baked MSX1 to MSX2 computer which unfortunately makes it more limited than having a pure traditional MSX1 or an MSX2.

  5. Paco Santos Ramírez

    Hello Jim, nice you are making progresses with the MSX hardware, hope you reach your expectations and share the results with us.

    Please let me disagree with your conclusion regarding that nobody uses the MSX for making music, it depends of the point of view. Professionally? You are right anyway I wouldn’t bet is 100% true. On the other hand if we are talking about the past and current MSX scene the MSX software database contains hundreds of compositions done by users not only for games but for music demos and/or the pleasure of composing using the different MSX soundchips such as PSG, SCC (Konami Sound Custom Chip), YM2413 (MSX-MUSIC), Y8950 ( MSX-AUDIO) or YMF278 (Moonsound or OPL4) or even MIDI devices. This means that music is one of the best, maybe the best, feature of the MSX standard. Take a look to the Youtube videos…

    I you want more info about it, I recommend visiting the msx.org taking a look to the wiki section of the MSX standard. Let me add here the direct link to the music expansions just in case you are curious. Regards.


    1. Let me vehemently agree with Paco here :). There is a ton of music made for MSX and still being made. I think MSX is also one of the systems with the most sound expansion cartridges available for it: FM-PAC, Music Module, MoonSound, Konami SCC… However the Yamaha CX5M / SFG-05 isn’t used much, it’s true. Although it’s great hardware, it simply was not mainstream enough, the cartridges I mentioned were much more generally available.

      People generally use trackers such as MoonBlaster, Trilo Tracker, Vortex Tracker, etc. Especially in the 90’s everybody was making music disks (I’ve been involved in three of them myself :)). Check for example johnhassink’s Youtube channel, or search Youtube for “trilo tracker” or “moonblaster” for tunes.

      I myself am right now working on a piece of software called Synthesix which turns an MSX into a MIDI synthesizer module :). Also the Trilobyte guys just finished their Trilo Tracker for SCC, and an FM-PAC version is coming soon. TNI is working on a great MoonSound tracker. And a lot of great music is being composed, often used in games, but also outside. Just recently msx.org had a game cover challenge with 20 songs submitted, some made on the MSX itself. So, lots of music-related activities going on!

  6. Jim, I am using DMSII (DMS1 MK2) via MegaFlashROM on my CX5M – the trick is really the RAM. I use the MFROM with 512KB RAM, which supersedes the internal 32KB of the CX. I am using the ROM that Gerritt from CX5M.net created. The MFR lets you hold all available Yamaha ROMS on a SD card, allowing you to select which to boot via a MultiROM boot menu. I highly recommend this solution, as it also lets save save, i.e. manage sounds for the internal 4OP, and external DX/TX line. Like you I am owning a TX816 (+ QX1, MV802 etc). However imagine this setup with three CX5 computers: CX #1 with DX Voicing (to control TX816), CX #2 with MIDISLAV 1.5 (for internal 8-part multitimbral 4OP), and CX #3 with DMSII to midi sequence them all via its 16 tracks. 80s Yamaha nerd bliss 🙂 … if you haven’t done it already get yourself a MFROM.

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