Intellivision ECS Keyboard Repair and Demo

And welcome back to another episode of 8-Bit
So, recently a fan of the channel named Alex
called me up and offered to ship me this keyboard,
which is an accessory for the Mattel Intellivision
gaming console.
Well, I thought, wouldn’t that be interesting
to try to make some music with that?
So, I’m like “Sure go ahead and ship that
And I thought this device, since it is made
by Mattel and it’s specifically for the
And I thought, well, this will just plug right
in to the game console and then there would
be maybe some kind of cartridge that had some
kind of musical software on it.
Well, it turns out it doesn’t work that
way at all.
So, let’s have a look at how it really works
and see if maybe I can make some music out
of this thing.
This is the Intellivision musical synthesizer.
It has 4 octaves or 48 keys, which isn’t
And as you can see, this is an official 1st
party product from Mattel.
However, take a look at this connector.
It’s two DB9 connectors, similar to the
joysticks used by Atari, Commodore, or even
the Intellivision itself.
But where does this plug in?
If you look at the console itself, you’ll
notice it has only a single DB9 connector
for each controller, but they are much too
far apart for this thing.
So, that’s where this thing comes into play.
The Intellivision computer adaptor.
I first became aware of this device recently
when visiting the National Video Game Museum.
I also saw there was a similar device for
the Atari 7800.
So, if you open this cover you’ll see the
connector that will match up with the musical
And the way this works is it slides into the
side of the Intellivision.
And not only do you need to power your Intellivision,
but the ECS module also has its own power
cord as well.
And of course, it’s primarily made to work
with this computer keyboard.
And this keyboard has that same funky connector.
So I’ll just plug that in here.
Now, when I first powered on my Intellivision,
I just got this black screen.
I actually thought something was wrong with
the unit.
But what I eventually figured out is that
you have to insert a game cartridge.
It doesn’t even really matter which cartridge
you use.
I’ll use Frogger here for an example.
Now when I power it on, I get this screen
saying the ECS is connected.
Pressing any key on the controller will bring
up this menu.
There are 3 choices.
If I pick 2 for cartridge, it will start whatever
is on the game cartridge, in this case frogger.
And, everything works pretty much like you
would expect.
If I power cycle and choose 1 for BASIC it
will take me to a BASIC screen, much like
you would expect from a vintage computer.
It uses a strange dialect of BASIC, though.
Some commands are abbreviated.
For example, you type PRIN instead of PRINT.
The keyboard is pretty terrible, not just
because it is a chiclet keyboard, but also
the location of many of the keys is irritating,
such as the backspace, which is actually the
left cursor key.
One thing that is interesting is that when
it parses a line, it highlights the different
parts of the code in different colors, which
is kind of neat.
So there we go, my incredible program.
Interesting to note that when listing, it
doesn’t show the color codes.
Anyway, here we go.
BASIC is pretty hard to do anything interesting
on this platform.
Also the characters are huge, probably a result
of the low resolution of the Intellivision’s
video chip.
In fact, it appears you only get 20 columns
by 12 rows, which is actually considerably
less than a Commodore VIC-20.
The ECS unit also has ports on the back to
connect a cassette recorder and that way you
could load and save your BASIC programs to
a cassette tape.
Now, it’s no terrible surprise that this
unit was a terrible flop on the market and
there’s a fascinating history as to why
Mattel produced it, and of course why it flopped.
Maybe eventually I’ll do an episode on that
on my other channel, but for now let’s see
if we can make some music.
If I reset it again, and this time select
3 for music, I can actually play music on
the QWERTY keyboard here, but the notes are
not in any particular order.
So it’s just about random what note you’ll
So, yeah, that’s pretty useless.
So, what I’ll do now is unplug the QWERTY
keyboard and attach the musical keyboard.
Well, that works a little better.
Yes, it’s showing sharps on the screen here
even though I’m not playing them, but I’ll
explain why in a minute.
The first problem I noticed is this.
Yeah, some of the keys just aren’t making
good contact anymore.
I can probably fix that.
Then I wanted to test the polyphony.
And I wasn’t surprise to see I could hold
down 3 notes at once.
But I actually discovered it could do 6 notes
at once.
This really surprised me.
You see, the Intellivision uses the General
Instruments AY-3-8910 sound chip.
I happened to know this chip pretty well,
since we’ve been using it in our prototypes
for the Commander X16 up until recently.
And so I knew those chips only had 3 voices.
So, then I discovered that the ECS unit contains
an additional sound chip, giving it a total
of 6 voices.
The only controls I can seem to find is that
if you use the buttons 1 and 3 on the controller,
it will transpose the entire keyboard by 1
half step, which is why you were seeing sharps
earlier because I had been playing with that
before recording.
If you use buttons 4 and 6 it will transpose
by an entire octave.
And that is pretty much it.
I mean, that is the extent of the music making
There are no different instrument types to
pick from, or ADSR, or rhythms or anything.
It turns out there was a cartridge made called
Melody Blaster.
It worked kind of like a modern-day guitar
I wasn’t able to get ahold of the cartridge
in time for the video, but here’s a clip
from Arcade Database, which they said I could
And this is about all the cartridge did.
It really didn’t allow you to create music
or anything, it was mostly just learning to
play whatever songs were built in.
Obviously, the AY-3 chips are capable of considerably
more advanced sounds than this, but that’s
all Mattel seemed to think we needed.
Now, I did find a home-brew ROM called Sinthy
which allows the user to play some more complex
sounds, but I wasn’t able to figure out
any way to get this to work on my machine
in the amount of time I had available.
Before I can do any audio recording for this,
there’s two problems I’ve got to solve
One problem is that the Intellivision itself
doesn’t have any sort of audio output.
All it has is an RF output designed for you
to tune your television to channel 3 or 4,
and that’s how you would normally watch
your games and hear any sound that comes out
of the system.
Well, the only way I can use that would be
to either try to record from the television
itself or use some sort of RF demodulator,
which I really don’t want to do.
So, I think the best thing to do is to go
ahead and modify the Intellivision for composite
video and direct audio.
But, before I do that, there’s one other
problem I need to tackle.
I’m going to go ahead and take the keyboard
unit apart and see if I can clean the contacts
It’s pretty easy to take apart, as there
are just a few Philips screws on the bottom.
And there we go.
The top piece comes off, and then the keyboard
mechanism is now accessible.
The inside is pretty dirty.
There are dust bunnies everywhere.
It’s no surprise it isn’t working well
It looks like I’ll need to remove this metal
And there are just a few screws holding that
OK, so how do we get these keys off?
Well, it’s not hard.
You just need a screwdriver and bend these
little clips back like this, and there you
go, the keys pop off.
So, I have a significant number of the keys
removed, but I’m actually a little bit at
a loss to figure out where the conductivity
takes place.
I’m thinking maybe it’s under this foam
Regardless, this board is really, really gross,
so again, not surprised that it’s not making
good contact.
OK, I’ve removed all of the keys from the
keyboard, and unfortunately, I’m not going
to be able to remove the PCB.
The main reason is the way it is attached
to the frame, where they have essentially
melted the plastics to hold it down.
So I’ll have to clean it in place.
I’m going to peel up this foam and see if
there are contacts underneath.
Yep, there they are.
This is a bizarre method of detecting keypresses.
The actual construction of the keyboard isn’t
really bad.
I’ve seen much worse.
But the contact system here is probably the
cheapest most horrible design I’ve come
across so far.
Well, I’m going to put this back down for
now and rinse the keyboard off.
I took all the parts outside and gave it a
good spray to clear all of the dirt and dustbunnies
out of there.
I still don’t know what to do about this
foam situation.
I’m going to try cleaning the board with
deoxit and then scrubbing everything really
But that only cleans one side of the equation.
And to be honest, I don’t think this part
is even the part that has failed.
This is a mind bogglingly dumb design.
It appears to be 3 parts, you have a plastic
strip with holes, some foam, and then conductive
paint or something on the foam.
I think for the moment I’ll try just putting
this back down and seeing if there is any
chance it will work.
I have the top of the board and the foam dried
off pretty well, but there may still be residual
water on the bottom side of the board, in
which case it may take a few days for that
to dry since I can’t get to it.
But I’ll just attach a single octave of
keys and see what happens.
I also took the liberty of cleaning the keys
since they were pretty gross as well.
OK, here we go.
It sounds like DTMF tones for dialing an old
I guess it thinks more than one key is being
pressed down.
I pulled the foam back off and decided the
best way to deal with this would be to try
to recreate a new foam pad.
So the first step was to attempt to get all
of the old adhesive off of the PCB.
The next step was to see if I could separate
the foam from this plastic spacer.
This will save me some time if I don’t have
to try to manufacture one of these myself.
Fortunately, I found that with some work I
was able to get most of the foam off.
But it was still covered with a small layer
of the old foam.
Here’s what the original foam looks like
without the plastic spacer.
I’m pretty sure they just painted the conductive
area right onto the foam.
I can’t feel any other material here.
I wanted to see if I could clean up that spacer
a bit more, so I went for the WD-40 and let
it sit for a while.
Then, combining that with some alcohol I was
able to get most of the rest of the material
to come off pretty easily.
And here is the plastic spacer all by itself.
It’s barely recognizable.
So, this is how it goes down on the PCB, and
eventually we’ll have to put some new adhesive
on this to hold it in place.
But, I have to find some suitable replacement
I started at Joann, as I thought surely they’d
have something like this.
I mean, they have every kind of craft thing
in the world.
But all I could really find was foam like
this, which was much too limp and probably
made for stuffing into blankets and stuff.
Of course, they did have some other kinds
of foam, but this stuff was way too thick.
So, my next stop was Hobby Lobby.
Surely, they would have something, right?
I mean, they do have a variety of things made
from foam, but not really the sort I’m looking
I suppose if you need a pair of balls, they
do keep those in stock.
Next stop was The Home Depot.
You know, this is really so typical.
People always wonder why it takes me so long
to make videos, well it seems like nothing
ever goes right or goes as planned and I’m
always trying to solve problems like this.
Hey, it looks like they sell 3 dimensional
icons for VLC player.
So I did find some various types of foam here
in the store.
But I didn’t think any of these would likely
It really just seemed too thin.
However, this foam double-sided tape caught
my eye.
I don’t really need the double-sided part
of it, but it does solve the problem of having
to use adhesive at least on this part.
OK, so here’s some of the stuff that I bought,
and I’m just going to have to try several
of these and see how they work.
So here’s one type of foam that I managed
to find from a friend.
And this is something I found around the house.
It’s just some packing foam.
Probably not going to work.
And then this is the double-sided tape I bought
at the hardware store.
And of course I have to figure out how to
make little bits of it conductive.
So, one possibility is I’ve got this copper
tape here, which could be used.
I’ve also got mylar that is conductive on
one side, but not conductive on the other,
I think.
So, I might be able to punch out little circles
of that.
And, I’ve also got some conductive paint
that I can try actually painting onto the
foam itself, which is kind of how the original
product was designed.
So, I’m not going to give you all the details
on this.
I’m going to experiment here a bit and I’ll
get back to you and see what I found.
Of the many experiments I did off camera,
the most promising one was to use the aluminum
coated mylar in combination with the foam
I tested it with my fingers first, and as
you can see, it works.
Of course, I can’t use one long strip of
the stuff, because that would interfere with
being able to play multiple notes at once.
So, I used this punch to punch out some little
circles of the mylar.
All right, so I have cut myself out some of
these little guys.
I’ve got about 50 of them here.
And one problem with these is that they’re
only conductive on one side because they’re
mylar coated.
So, I’m going to have to test each individual
one with a multimeter to figure out which
side to put them on, but anyway, hopefully
these will work.
Next, I unrolled a sufficiently long piece
of the foam tape.
And here’s the tricky part.
I need to be able to mark where the circles
go, so I’m going to very lightly place the
plastic spacer onto the sticky part of the
tape, but hopefully not get it stuck permanently.
Then I’m going to use a sharpie to mark
the little circles.
And then I’ll remove the spacer before it
gets too comfortable being stuck there.
The next step is to test a little circle here
and see if this side is conductive.
And no, it isn’t.
So, I will flip it over like this.
And now I’ll test it again.
This is the side we need.
I tried to place these on the tape by hand,
but found my fingers were just too big.
So I ended up doing it with tweezers like
And here’s all 48 of the little circles
now in place.
Just to be on the safe side, I’ll go back
and test each pad to make sure the conductive
side is facing the right direction.
Unfortunately, as you can see, I did find
one that somehow got put on backwards.
I was concerned if I would be able to get
this thing back off without damaging the tape
or foam.
Fortunately, I did manage to remove it.
And, obviously, I replaced it with another
This next part is very delicate.
I got my wife to hold up the one end of the
strip so that I could carefully line this
spacer up as I worked my way down the line.
The circles don’t line up exactly, and I
didn’t figure they would.
In fact, they are slightly larger than the
holes in the spacer, which is why I needed
to put them down on the foam in the first
place like I did.
OK, time for a test.
Right now this pad is not sticky in any way
on the bottom.
So I can just slide it under this one key
I’ve placed back on the keyboard, so I can
see how it works.
And it seems to work.
I’ll give you a little closeup here so you
can see exactly what is happening.
Since it looks like this is going to work,
I will need to put some new adhesive down,
but this will also be tricky.
The way I’ve decided to do this is to mask
off everything I can, and use 3M spray adhesive.
Of course, I definitely have to make sure
to cover up these conductive points, otherwise
the adhesive will ruin the whole thing.
So, the idea is, we just want adhesive between
these spots.
So, I’ve got everything masked off.
This will give you an idea of where the adhesive
is going to go.
And here’s the 3M spray I’m going to use.
I’ll only get one shot at this, so here
goes nothing.
OK, let’s peel up this masking tape.
Let’s take a quick look at the adhesive.
It appears to be exactly where it needs to
be, right between the pads.
OK, here’s another thing I only get one
shot at.
I need to line this up just perfectly.
OK, so far so good.
I’ll just press it down.
And of course, now it’s time to re-attach
the keys so I can see how it’s going to
The good news is, all 48 keys are working
So, time to re-assemble the keyboard.
And ran into another problem.
When I re-assembled the keyboard, I found
the case had a stopper that prevented the
keys from going down far enough to actually
engage the thin layer of foam I used.
So to counter-act that, I simply removed the
little wax paper thing on the other side of
the double-sided tape, and then added another
layer of double-sided tape on top of that.
Then, reassembled it all again.
All right, so I’ve got good news and I’ve
got bad news.
The good news is that all of the keys on the
keyboard are now currently working.
The bad news is, they’re probably a bit
more stiff than they ought to be.
As far as, it takes a little bit too much
pressure to push the keys down.
When I tested the foam on a single key, you
know, that’s one thing, but it’s not quite
the same thing as actually trying to play
a tune.
And so, obviously this could be fixed.
All I would need to do is take it all back
apart and then basically do the exact same
hack I already did, only find some other foam
that’s a little bit less stiff.
And but, guess what?
I’m actually not going to do that.
This was supposed to be a 5 day project and
here I think I’m at day 12 already.
And plus, I had promised to modify the Intellivision
to put the composite video mod and I’ve
already got the little circuit here for that
as well as wire up direct audio so that I
could record some kind of performance.
But that would probably add another 4 or 5
days to this long overdue project so I’m
really just going to have to move on with
So, what I’ll do is, I’ll probably do
the composite mod on a different video, probably
on my other channel the 8-Bit Guy.
So, until then, I guess that about wraps it
up for this episode.
So, as always, thanks for watching!


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