Yamaha CX5M Music Computer

Click here for shots via this auction.

Note the connection of this piece and Microsoft? If anyone knows more about the relationship feel free to comment.

"You are looking at a Yamaha CX5M Music Computer. This unit came out in the very early 1980's and was an attempt by Yamaha to marry what was emerging as a very successful exploration of FM Synthesis and a computing platform, in this case the Microsoft MSX. At the time these units were unbelievably expensive and while I am not sure exactly what their true value is today (who is frankly) one thing I do know (and you too if you have read this far) is that they are becoming increasingly rare particularly those still bundled with the all important cartridges as this unit does, more on that later... the unit you are looking at here is in fact the later of the two models that Yamaha came out with. The first shipped with the SFG-01 FM unit which had very limited MIDI support, in fact it was only able to communicate with a DX-7 (again more on that later). For that reason you needed a dedicated keyboard supplied by Yamaha to play it. The unit you are looking at here however is the later version that came with the 4 Operator SFG-05 FM unit. It has much better MIDI support and DOES NOT REQUIRE the additional Yamaha keyboard in case you were wondering. It can be played with any MIDI controller keyboard, I used a JV-30 and it played very well.
Ok so what is on offer, well quite a bit really:

1) The CX5M Unit, apart from one or two very minor scratches it is in excellent condition, no broken keys or anything like that. The unit consists of the MSX computer fitted with the Yamaha 4 Operator SFG-05 FM module;
2) The power supply, as above in excellent condition and works just fine;
3) The manuals, yes I still have them. They include:
a) The Yamaha SFG-05 FM Unit Owners Manual;
b) The original CX5M Owners Manual; and
c) The original CX5M / MSX Service Manual including ALL the schematics (these are like GOLD).
4) The cartridges. These are VERY VERY RARE, they include:
a) YRM-104 - FM Music Macro, provides a basic software language to allow the MSX and the SFG-05 in particular to be programmed, oh what fun!!
b) YRM-101 - FM Music Composer, as the name suggests it provides basic sequencing and composition. You also get the original manual with this;
c) YRM-102 - FM Voicing Program, this allows you to edit the 4 Operator SFG-05 unit sounds just like any other FM style patch editor; and
d) I left this until last simply because you would be hard pressed to get one of these anywhere right now. The YRM-103 - DX-7 Voicing Program, This cartridge will allow a DX-7 to be edited from the CX5M just as Yamaha had originally intended so if you own a DX-7 this may be of particular interest to you. It comes complete with its original packaging (a little worn but intact) and the original manual.
5) The cartridge adapter, The CX5M also comes with a slot at the rear of the unit. I believe it was used for connecting to external floppy drives and the like. Using the cartridge adapter you can also plug a standard MSX cartridge into this slot. Useful I guess if you can get a memory / storage cartridge which you can store your programs and sounds on.

The unit DOES NOT come with a monitor of any kind, it has a composite video output (the yellow kind) which I connected to my PC's capture card in preview mode so that I could switch screens between it and other windows, quite useful when editing actually."

via Loscha.

Update: Two screen shots of the OS via Zam in the comments. Also, more info on the OS and the relation with Microsoft in the comments added below.