Introduction: Project C=BOARD

The goal of this project is to modify a Commodore 64 computer so that in addition to being a computer it is also a rockin musical instrument.

I'd like to thank the following folks who made this possible:
Nak - For his paddle design (though it was a wee bit off)
sch�nberger - for inspiring me to actually wear my C64
tomtiki for giving me correct schematics.
And finally Paul Slocum for making Cynthcart

DISCLAIMER!!! If you are not sure what you are doing ask someone for help. I am not responsible for any damage done to your C64, cherished childhood memories, or person, if you follow some or all of these directions. Be careful with electronics and ALWAYS UNPLUG THEM when working on them.

For this project you will need the following:
A Commodore 64 (any model)
A Soldering Iron
Some wires (color coded is good, though mine is not)
A Cynthcart cartridge (these can often be found on ebay)
2 500k Potentiometers
A guitar strap
2 1/4 inch nuts and bolts
6 Washers (big enough to fit on a 1/4 inch bolt)
Some paint to make your C=BOARD fancy!

Here's a sample MP3: Noise in A
And another 8bit2, this one also features a Korg DS10

Step 1: So, Exactly What Are We Doing?

Here's the plan. by the end of this we will have made the following modifications to a c64:

1. Get Cynthcart
If you just want to make music on your C64 this is the simplest way. Cynthcart is a solid sta6te cartridge that makes your c64 a synthesizer when you boot with it inserted. Most of the controls in Cynthcart can be done with the keyboard, though adding some knobs helps with certain aspects of it. Cynthcart can usually be found on Ebay, I got mine for a little over $20.

2. Paint it
Again, this is optional, but if you are going through all this trouble to mod your c64 you might as well give it a little war paint.

3. Add a strap
Sure, you could just sit it on a table and play it, but to truly rock out you need to WEAR an instrument. Thus the C=BOARD is also a C=TAR.

4. Add 2 control knobs
These knobs will be used by Cynthcart for a few different functions. While most of this can be done just using the keyboard, the knobs give you greater control and easier more analog input.

Step 2: Paint It!

If you are going to paint up you C64 you might want to do it before the other mods. Once the extra knobs, button, and strap are installed it'll be a lot harder to paint (trust me, I know this from experience).

Before disassembly, remember these things: Don't lose your screws, keep something handy to put them in. And always check that you are static free before handling circuitry, Simply touch something grounded once in a while while working.

First, we need to disassemble the c64. Not as hard as it sounds. On the bottom towards the front are three screws. Undoing these and carefully turn it right side up again.

Now you can open the C64, it pivots open like the hood of a car, with the clips at the back working sort of like hinges. Be careful as you do this since the top of the machine and the bottom are still connected by some wires. On the left is a ribbon cable that connects the motherboard to the keyboard. Take note of it's orientation and carefully remove it. Do the same with the small wire on the right that connects the power light to the mother board.

Now remove the screws holding in the mother board and remove it. Then remove the keyboard from the top half of the case. Note that there are a lot of little screws in the keyboard and a few medium sized ones around the edges, you only need to remove the medium screws to get the keyboard out.

So now you have the two halves of the case separate from all the electronics. Next put some masking tape over the c64 logo and the power light and power logo. Make sure that the tape is down real good and cut away excess tape with a sharp hobby knife or razor blade.

Now you may paint it however you want. I used a red krylon spray paint made for plastics for my base but I think other paints should stick to this plastic. I then masked off a racing strike and painted that with white primer.

Step 3: The Strap

For true rock star effect you should wear your instrument. The C=BOARD is no exception.

I decided to use a standard guitar strap because I had one handy, but other straps could work too. While there are better ways to have done this step there are few easier ways. Feel free to try your own idea, this is just what I did.

I drilled holes in the case, about 1/4 inch I think. I put them in the lower case, about and inch or so from the front. There's room for hardware in that spot and the plastic is fairly thick there. The nut, bolt, washers and strap combination provides some support for the case and a really sturdy connection.

Here's the order of things going on the bolt shaft:
washer, strap, washer2, goes through case into: washer, nut
Think of the washers as the bread in this industrial sandwich.

Step 4: Knobs

This gave me a little trouble and you need to have a little skill with a soldering iron. While this electronics job is very easy you do need to know basic soldering technique.

Note: If you are afraid to solder on your C64, you can instead make a paddle box that plugs into your joystick port. There's a link in the next step to an Instructable on how to build one.

Basically what we are doing is connecting two 500k potentiometers (pots) to the number one joystick port. They use the paddle circuits to give your synth some analog controls. Now I want to leave the outside of the port unchanged so I can still plug a stick into it can play a good game of Zaxxon, so I have to solder my pots to contact points on the bottom of the motherboard.

The C64 mother board has a thin sheet of metal on the bottom, soldered to the edges, this is the universal ground for the board, between the rest of the board and the sheet is a sheet of insulator (cardstock). You will need to unsolder a few of the contact points for the ground sheet on the right side of the board so that you can bend it back to reveal the bottom of the joystick ports.

Now solder the pots to each other and the board following my handy diagram. Finally, drill some holes in the top of your C64 to put the pots into. There's a lot of open real-estate in the top of a C64 so you have some aesthetic options.

Step 5: ROCK OUT!!!

So now you should have a fully armed and operational Commodore 64 keytar. I'd like to thank my wife for understanding my 8-bit rock needs, and my cat Tidbit for assisting in the wiring (see below). You may have noticed that my C64 has an extra button, this is a warmstart reset switch. I was going to provide a step on installing it but it seems that there are different ways for different models of c64, so I chose to skip it. If you want your own there should be instructions available elsewhere on the web. Or bug me and I will eventually include it with this Instructable.

Here are a few links that may help if you are having trouble.
Pot instructions for MSSIAH
Explanation of the joystick port
Nak's homebrew paddle box instructable(good if you don't want to solder on you C64)
Technical Overview of the Commodore 64

Comments

author
wanna beco (author)2012-09-13

That's cool, how did you build that cat in the last pic.. it also looks very real! (not trolling btw, I loved your ibl!

author
Crucio (author)2012-06-17

Love the attached music! Jogged some old childhood memories. Big thanks for that!

Post more if you can.

author
doomsdayltd (author)2011-08-04

how are the cynthcards? im thinking of getting a MSSIAH card for my c64

author
D10D3 (author)doomsdayltd2011-08-04

MSSIAH has a lot more flexabilities and a ton more features. On the other hand, Cynthcart is super simple to operate and instantly turns your c64 into a musical instrument without any setup or peripherals (short of some speakers to hear it). Cynthcart is simple enough to use that you can use it without a monitor. All of that said, I also want MSSIAH for it's more advanced options.

author
doomsdayltd (author)D10D32011-08-04

well i would like the portability of the Cynthcard but again i've seen the features for a MSSIAH. pff oh well this is just an instructable to make a c64 keytar, but yea thanks for clearing things up for me :D

author
EZtrollin (author)2010-06-07

i was so planning on doing this before :( i thought i had an original idea, kudos to you though

author
dphc (author)2010-05-12

Sweet, and you can still use it as a regular C=64!  The music samples are great too, sounds like it's straight out of an 80s game.  Does your cat Tidbit jam with you? :)

author
datenkrieger (author)2010-02-22

Nice one, very inspiring. Just got a cynthcart, built a knob box and checking out the sounds that can be made. Gonna add the feedback mod - routing the audio out through a 500K pot back into audio in - for some screaming self-oscillation.
Maybe routing some gameboy percussion through the filter...
But my C128 is too heavy for a keytar, need to get myself a C64. Too bad, they dont seem to be really cheap anymore (on ebay at least).

author
Fenwick (author)2010-02-03

Love the paint job.

author
Microscope (author)2009-12-02

So I've added the pots and it doesn't seem to work.  When I turn the paddles "on" it gives a brighter sound and the paddles "off" give a muted sound but turning the pots doesn't affect the sound.  When I plug Atari paddles into port 2 though it works.  

author
D10D3 (author)Microscope2009-12-02

I'd suggest checking you wiring, can you get a picture of where you've soldered the contacts?

author
Microscope (author)2009-11-30

When you say you're soldering to pins 5, 7 & 9, it looks like (according to the markings on the board) that you're actually soldering to pins 1, 6 & 8.  Should I follow the drawing you have or the markings on the board?  Thanks.

author
D10D3 (author)Microscope2009-11-30

I understand why it might look like that. The diagram isn't showing the joystick jack as you see it on the side of the 64, the diagram is showing the solder points for the jack that are on the bottom of the C64 motherboard, so they are transposed from what you might expect.

author
Microscope (author)2009-10-22

Audio or linear taper pots?

author
D10D3 (author)Microscope2009-10-22

I'm using generic audio pots for this project.

author
D10D3 (author)2009-08-10

By request I added some MP3s

author
Lazyazz430 (author)2009-07-26

Just some constructive criticism. C=B (Tilt your head) maybe change the name ;)

author
Llamarama (author)Lazyazz4302009-08-09

You can't beat a bit of immature toilet humour! Made me smile! :D

author
D10D3 (author)Lazyazz4302009-07-30

Dude...(shakes head)

author
depotdevoid (author)2009-08-01

Hey, awesome instructable, you get my vote! Can you post a video or an mp3?

author
Nick Carnally (author)2009-07-30

Dammnit Jaybles, now I have to buy a soldering gun, head to zerns / any flea market, and start scouring them for robo-Frankenstein parts. Very cool, and looks like a lot of fun.

author
lemonie (author)2009-07-25

8-bit! Can you post an audio file? L

author
robotguy4 (author)lemonie2009-07-27

I 2nd this. Music suggestion: Do the Tetris theme song over and over again until you pass out! (or not...)

author
stephenniall (author)2009-07-25

Omg i love this i want one ! lol

author
night (author)2009-07-24

Amazin work my man, put up a video of the rocking out,

author
brunoip (author)2009-07-24

amazing :O

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