The Yamaha CX5M Music Computer was one of a number of MSX computers released worldwide in the 1980's, as well as one of only a few marketed in the United States. Project CX5M is my attempt to document this vintage computer, and I want to give it a proper treatment.
I know that many of my US-based readers have never heard of the MSX standard. That is understandable, as MSX largely bypassed the United States. Only two companies marketed MSX computers in the US (with Spectravideo being the other company, if you're curious).
Anyways, Yamaha's CX5M Music Computer is a notable entry in the annals of computing history. While I have found evidence that computers were used in the music production process, as well as marketed for their sound generation capabilities prior to the CX5M's release, the CX5M may be the first computer specifically marketed for music production.
After all, Yamaha was no stranger in the music industry. For example, their DX7 synthesizer created some of the most iconic sounds in 1980's pop music, though programming new sounds on it proved to be difficult.
And yes, Yamaha sold a cartridge for the CX5M that could be used to more easily create new sounds for the DX7. It was among the first set of cartridges launched for the CX5M.
You might be wondering why I would even bother with physical hardware at all. Any CX5M hardware that I do find is going to be over 30 years old. And interfacing modern hardware with vintage computers can present a unique set of challenges.
For example, while MSX-DOS used the FAT12 file system, macOS no longer supports external USB floppy drives. Fortunately, Linux and Windows still do... but for how long?
And it's not like you are going to drive down to your local office supply and find a double-density floppy disk to use in your vintage computer. (Fortunately, eBay is a good source for new old stock disks.)
Also, vintage computers usually output video at a non-standard 240P, instead of the NTSC standard 480i. CRT-based TVs were totally fine with displaying 240P – and if your TV was small enough, you would never notice the missing scan lines were missing from the signal.
However, since 240P was never a standard, many modern TVs and video capture devices will flat out refuse to acknowledge that there is a signal.
Furthermore, some video controllers of the day, including the TMS9918A found in the CX5MU (that's the designation for the US-market CX5M), did other tricks in the name of making video output computationally easier. Unfortunately, these non-standard tricks cause undesirable artifacts in modern video equipment, as shown in these examples.
These vertical lines are the evidence that the video signal isn't quite NTSC standard. 
Some capture devices won't try to decode the chroma signal due to the standards deviation. 
And some devices make a hot mess of everything... 
Here's the best still frame capture I managed (without use of a vintage computer-savvy upscaler). It's usable.
I'll elaborate on these "tricks" in a future post.
But emulation also has its drawbacks. MSX emulators do exist, and they have support for the CX5M. Some emulators let you record the screen, which would result in a far better picture than composite video could ever provide. Or if the emulator didn't support this feature, screen recording software could come to the rescue.
Emulation also would not let me experience what it was like to actually have a CX5M in the 80's. And there is a certain je ne sais quoi from hearing the sound from the actual synthesizer hardware, instead of an emulated approximation.
That is, if any of the MSX emulators even attempt to emulate the SFG-01 and/or SFG-05. I have so far been unable to get far enough with any of the MSX emulators to make that determination.
Therefore, I will press forward with using actual CX5M hardware, but will still investigate using MSX emulators to help fill in gaps in the story of the Yamaha CX5M Music Computer.
