Hello and welcome back to 8-Bit Keys.
In this episode, I want to show you this fascinating keyboard called the Yamaha PCS-500.
And, you know, what it looks like, is it looks like a keyboard case, with possibly a keyboard
in it.
But, this is the actual keyboard.
Not just the case.
So, here's how this works.
You just pull this up, and fold it over, and voila, you've got the keyboard and a music
stand all built into one protective case.
Now, while that's pretty cool, it's by far not the coolest thing about this keyboard.
And the coolest thing is that it uses the Yamaha play-card system.
So, let me show you how that works.
Let's take a closer look at the keyboard.
It's a 49-key setup, with the smaller or miniature keys.
It has a very similar setup to many of the Yamaha keyboards of the era, with the style
of buttons and sliders.
The instrument selector, or orchestra as Yamaha likes to call it, uses radio style buttons.
So these physically allow you to select one instrument, and it pops out whatever was selected
before.
One nice feature about this is that the keyboard will remember which instrument you were using
after a power cycle.
Let's take a look at the rear.
It has stereo line output jacks, which I will go ahead and connect to so that I can give
you clear audio of what you'll be seeing shortly.
I will also be powering this from external power.
I should also point out that it has a microphone input, along with a volume control knob.
This is most likely so that you can sing along with whatever you are playing.
Next, I want to give you an overview of the 10 different instruments it has.
I'll start with the piano.
Let's try adding some sustain to that.
Now let's try the stereo symphonic.
This thing does have 7 polyphonic voices, by the way.
Also there is a transpose feature here.
You can go down 5 half steps, or up 5 half-steps.
OK, so let's try out all the instruments
Of course, there are a variety of preset rhythms you can use as well.
As you can imagine there is some auto chords for the rhythms too.
So, now that I've shown you the keyboard itself, let me show you the play-card system.
This is a piece of music.
This particular one is Dancing Queen by Abba.
On this side you have lyrics and information about the overall song itself.
On the other side we have the actual sheet music.
Now, let me pull it out of this protective sleeve.
Notice this black stripe down here, this is a magnetic strip, that works much the same
way a credit card stripe works.
If you just want to try playing the sheet music, you can sit it right here.
But if you want it to do it's magic, you do this.
As the music plays, the melody will light up on the keyboard to help teach you the notes.
Perhaps you'd like to play some Christmas music?
Looking at the sheet music, I noticed that all of the music I have appears monophonic,
in that you are only given single notes at a time.
It does appear there is also an additional monophonic background track that is not shown
on the sheet music.
In fact, thinking about this, I've determined there is quite a lot of information stored
on that magnetic strip.
After all, there's the rhythm selection, instrument selection, tempo, a melody track,
a background track, and chord selection for the accompaniment.
The data stored on this magnetic strip, is really similar to what you might see on a
credit card or a drivers license, it just so happens to be a lot longer so that it can
store a lot more information.
But, the actual technology for reading and writing to those strips is actually really
similar to what you might have with an old digital cassette drive like this.
The read head is almost identical and the stripe on this play-card is pretty similar
to if you just had a piece of cassette tape media glued to a piece of paper.
In fact, I wondered what would happen if I ran this play-card through one of these square
gadgets and recorded the sound.
And here's what I got.
It sounds, not surprisingly, very similar to listening to a computer program stored
on a cassette tape.
What I did find interesting is that it has 4 distinct sections, but I can only guess
at this point as to what they are.
It would certainly be possible to analyze this information and work out how the information
is stored, but I imagine it would take me months or years to figure it out.
Maybe I'll let somebody else do that.
This new Yamaha Portasound has the exclusive Yamaha play-card system, which can turn you
into an instant keyboard player.
Slide in a play-card, and watch the melody lamps.
They show you which keys to play.
See, and the built in band will even wait until I get it right.
So, how does this compare to Casio's ROM pack system that was popular around the same
time period?
Well, in terms of information stored, they seem to be virtually identical.
However, I suspect there were some trade-offs in terms of cost.
For example, I'm pretty sure the ROM cartridge probably cost more to manufacture than one
of these play-cards.
But, one trade-off might be the fact that the Yamaha would require an extra RAM chip
inside in order to basically copy the information from the card into RAM in order to be able
to play it.
In fact, its clear the Casio keyboards read straight from the ROM pack because if you
pull one out while it is playing, the music will stop.
However, then it occurred to me there is one other difference.
These ROM cartridges can hold multiple songs.
In fact, I have seen some that have as many as 20 songs onboard.
So in theory you'd need as many as 20 of these play-cards to accomplish the same thing.
So, that may have made up some of the cost difference in producing these.
So in that regard, the Casio system does have one advantage.
The best I can tell, there were only 7 or 8 Yamaha keyboards that supported this format.
And the format died out after just a couple of years, which is kind of surprising, whereas
the Casio format continued for many, many years and they used it on dozens of different
keyboard models.
However, despite being short lived, there is no shortage of play-card titles available,
although the vast majority of the music is from the 1970s or even older.
It appears that quite a lot of it was sold as a set, so you would essentially buy an
album like this one and it comes with a bunch of songs.
Also, there is a special cleaning card that is used to clean the head.
It has a fabric like feeling to it, and you just run it through like this to clean the
head.
OK, so the only thing left to do now is disassemble it!
I have some sneaking suspicions about what I'm going to find, but I won't say anything
until I confirm it.
Ok, well the back of the case lifts off easy enough.
And it certainly appears that there are a lot of DIP package style chips on the other
side, but it isn't going to be easy getting to them.
Fortunately, Yamaha usually uses connectors that can be disconnected, unlike Casios from
this same time period where everything is soldered on.
So this does make things easier.
However, I'm still not able to get this board out due to the speakers.
So I will have to desolder these.
Fortunately, they are easy to reach and this was super easy.
OK, so I can finally turn this board over and we can have a look.
Unfortunately, most of the chips are up-side-down from this angle, but that's okay, I'll
make it a bit easier for you to see.
So this is a clone of the Intel 8085 microprocessor.
This was used in a lot of electronics at the time, including other keyboards, and even
some personal computers.
And over here is a Yamaha IG10771 synthesizer chip.
This is one of the last synthesizers they made before switching everything to FM.
I have one other keyboard that uses this same chip, which is the Yamaha MK-100 which I've
shown in a previous video.
I suspected the sound chip would be the same being they were made around the same time
and sounded almost identical.
I have always said this chip reminds me of a Commodore 64's SID chip with a lot more
voices.
This chip here, I'm not 100% sure about, but one website related to a different Yamaha
keyboard said it might be a matrix decoder, which would have to do with reading the state
of the keys.
And over here, not surprisingly is a ROM chip, followed by 2 RAM chips, each one is a 2K
static RAM giving a total of 4 kilobytes for this keyboard.
And the last chip is a generic Mitsubishi chip which is a parallel port, most likely
it is used to read the various buttons on the top of the keyboard.
And last, of course, I want to show you the read head for those play-cards.
It's kind of buried in there, but I think I can get it out.
OK, it seems to be held in with a spring, so let's see if I can get that apart.
And here we go.
So yeah, just as I suspected, it looks really similar to the read head on a cassette drive.
So from a perspective of sound capability this keyboard is virtual identical to the
Yamaha PSS-260 and PSS-450 which both use the same sound chip and have similar number
of preset instruments.
And of course the MK-100 that I have also uses the same sound chip, but is infinitely
more customizable.
All right, well that about wraps it up for this episode.
I do want to apologize that I didn't do any kind of multi-track recording.
I had actually planned to do that, in fact I spent a whole day trying to come up with
a song and I just… it was just one of those days I just couldn't get inspired.
I just couldn't come up with a tune that I wanted to work with, so I just decided I
had a lot of other stuff to cover on this keyboard anyway, so I just decided to skip
it.
But, on the bright side, I do plan to do multi-track recordings eventually on one of this keyboard's
cousins, one of those other 3 keyboards I talked about that share the same sound chips.
So, in essence some day you will hear a multi-track recording on this, in a different episode,
even though it will be a slightly different keyboard.
Hopefully that's some consolation.
Anyway, that about wraps it up, so stick around for the next one and thanks for watching!
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