DeCosa's Joy of Joys Keyboard

DeCosa's Joy of Joys Keyboard instructions.  Formatting of document mutilated by MS-Word HTML converter.  The original document looks much better, and it's downloadable here.  The keyboard matrix at the end of this document in particular was horribly mutilated.  As time permits I may try to clean up the formatting.  --- saint

** Thanks for letting me use this Tony! **


Joy Of Joys Keyboard:
How To Do It!

Tools Needed:


Soldering Iron

Hobbyist's Drill (Radio Shack USED to sell a plastic hand drill w/2 PC-board-hole-sized bits, but I don't know that they carry it anymore. Try a hobby shop.)

Hot Knife (Optional - Helpful if you're going to chassis-mount your connectors.)

Nibbling Tool (RS # 64-823) (Optional - Also helpful for installing chassis-mount connectors.)




PC Concepts Windows 95 Compatible Keyboard (Office Depot, Item # 459-560, $19.95)

Sega Genesis Control Pad Extension Cords (2) (Wal-Mart, $2.00 each)

High Frequency brand Super Nintendo controllers (2) (Toys 'R' Us, $10.00 each) (Optional)

DSUB-9 Male Connectors (2) (Radio Shack, RS # 276-1537, $0.99 each) (Optional)

Arcade Joysticks and Buttons (Happ Controls) (Optional)

DSUB-9 Female Connectors (2) (Radio Shack, RS # 276-1538, $1.29each) (Optional)



Keyboard Modification Instructions:


1. Turn the keyboard over and remove all the screws EXCEPT the three small ones on the left side where the plastic is raised.


2. Remove the three small screws now, and remove the back of the keyboard, being as careful as possible not to disturb the key membranes and the rubber key plungers beneath the membranes.


3. Remove the rubber pressure pad that presses the membranes against the circuit board, and remove the screw holding the circuit board to the casing. Now you can remove the circuit board and cable from the casing.


4. Put the keyboard itself aside, preferably somewhere that the keys can hang free: resting it on a roasting pan should work nicely.





5. Looking at the circuit board, you should now see 25 contacts running along the bottom: a grouping of 13 followed by a grouping of 12. These are the contacts between the PC board and the membranes; the first 15 contacts mate with the vertical planes while the last 10 mate with the horizontal planes. Imagine that the contacts are numbered 1-25 from left to right. The contacts that we will concern ourselves with are 2, 9, 13, 14, 15 (vertical) and 18-25 (horizontal). The applicable contact tracings are color-coded in the image above. (IMPORTANT NOTE for M.A.M.E. Users: If you're going to be using your controller primarily with M.A.M.E. and plan on installing the computer into an arcade cabinet, you may want to tap into contact 1 instead of contact 9; contact 1 will give you controller access to the "1" ("One Player Start") key without having to access the keyboard!) (Contact 1 also grants access to the "Tab" key for the M.A.M.E. menus.)


6. Next you will need two DSUB-9 male connectors, either chassis-mount or as a cable-end connector. Chassis-mount connectors make for a more professional finished product, but its far more convenient to use the other end of the Sega extension cord that we'll be cutting to make our controller cables.


a. If you decide to go with chassis-mount connectors, mount them on the back of the keyboard casing near the circuit board; use the DSUB-9 diagram below and match the color coding of the 9 contact points to the same colors on the circuit board diagram above. (Note that both DSUB-9 connectors share the same vertical planes [2, 9, 13, 14, 15], but have separate horizontal planes [18-25].)


b. If you decide to go with cable-end connectors, cut your Sega extension cables so that two-thirds to three-quarters of the cable is attached to the PLUG END (female end) connectors. Strip and tin VERY SHORT LEADS from each of the 9 wires on both ends of both connectors. (NOTE: the conductors in the Sega wires are made to withstand snapping, and so are a thin copper coil encircling a filament rather than a standard stranded wire; due to the delicacy of these conductors, use the appropriate caution when tinning and soldering these wires.) Set aside the PLUG END portions of the cables for now, and solder the PORT END cables to the circuit board, observing the color-coding on the circuit board diagram above.


Male View (Port, not plug)



7. If using the cable-end connectors, tie a tight strain-relief knot in each of the D-SUB cables. (You MAY choose to add a notch or two to the keyboard bottom to allow for extension of the controller cables.) Now again being VERY careful to disturb the buttons/membranes as little as possible put the PC board back in, with the contact strip BENEATH the membrane(s), and with the cables in the proper recesses so they do not interfere with the replacement of the back cover. Put the screw back in, and replace the rubber pressure pad. Give one last check to make sure that none of the rubber key plungers are mis-aligned, and put the back cover on, making sure that the two tabs on the top edge are fitted correctly. Re-install all screws.


SNES Controller Modification Instructions:


1. Remove the screws from the back of the SNES controller; unsolder and remove the cable.


2. There are TWO different possible internal circuits for this controller: the surface-mount version and the conventional version. Of course, the surface-mount (SMT) version is more recent, and will PROBABLY be the type you will wind up with. Either is okay, though the conventional version may be a LITTLE bit more tricky to wire up. What is MOST important is that both controllers are of the SAME TYPE of circuit! (If you wind up with two mismatched controllers, buy a third, then return the one that doesn't match. Both controllers need to be wired identically so you needn't keep track of which is which when you plug them in.) I have only diagrammed the SMT version here, but the other is very similar.


3. Cut the tracings as indicated by the heavy red lines on the diagram to isolate the direction pad, the A-B-X-Y buttons, and the L-R-Select-Start buttons.


4. Cut around the perimeter of the SMT chip (the black enamel blob in the center of the board), making sure that ALL tracings are fully broken.


5. Using a hobbyist's drill, drill holes as indicated by the red dots on the diagram.



6. The white, black, gray and green planes (3 of each color) must be wired to the others of like color. To do this, you can either sand the tracings clean around the SMT chip and solder jumpers to the tracings, or solder jumpers to the holes you've just tapped into the board. (Jumping across near the chip is preferable, as wires inside the controller casing should be kept to a minimum.)


7. Using the PLUG END cables that we set aside earlier, solder the tinned leads to the SNES circuit board, matching the wire color to the diagram above.


8. Tie a strain-relief knot in the cables and reassemble the controllers, taking care to keep the wires from being pinched, or interfering with the buttons.



Arcade-Style Controller Instructions:


If you understood the concepts of what was done here, constructing arcade-style controllers to plug into the keyboard should be very simple. Here are some general notes:


1. Maintain consistency with your other controllers. We have just completed our SNES controllers, and we tied the direction pad common to connector pin 3 (orange); you will want to tie the SAME line to your arcade joystick common. Direction pad "up" is tied to connector 7 (gray); tie arcade joystick "up" to the SAME LINE. And so on. This will prevent your having to remap the keyboard each time you change from one controller to another. Below is a listing of the 2 connectors tied to each button on the SNES controller; tie these DSUB-9 contacts to the arcade controller accordingly.


UP: 3 7

DOWN: 3 9

LEFT: 3 5

RIGHT: 3 8


START: 6 9

B: 1 5

A: 1 9

Y: 1 7

X: 1 8

L: 6 7

R: 6 8


(IMPORTANT NOTE for M.A.M.E. Users: If you're going to be using your controller primarily with M.A.M.E. and plan on installing the computer into an arcade cabinet, AND you have tapped into contact 1 instead of contact 9 on the KBD circuit board, tie these contacts from the 2nd DSUB-9 accordingly:


COIN DROP (MAME key "3"): 2 5

ONE PLAYER START (MAME key "1"): 4 5

TWO PLAYER START (MAME key "2"): 2 9

MAINTENANCE (MAME key "Tab"): 4 9


2. Isolate the joystick and buttons from the cable connector. What do I mean by this? Well, if you're going to mount your controller in an arcade cabinet (and if you DO, make it removable by attaching it with cabinet latches), you do NOT want your hanging cable to be causing distress to your connections to joystick(s) and buttons. My recommendation is that you provide a "buffer"of sorts between your controller and your cable. Mount a DSUB-9 Female Connector to the underside of your control panel using a metal bracket or standoffs. Wires soldered to this connector should connect to the joystick/buttons using crimp-on quick disconnects. (Do NOT solder directly to the joystick(s) and buttons! Now you can use an intact "Sega Genesis Control Pad Extension Cord" to connect your controller(s) to your keyboard!




If you have any questions/comments, feel free to contact me via e-mail:


Have Fun!







Appendix 1: PC Concepts Windows 95 Compatible Keyboard Matrix


16 17 18 19 20 21 22 23 24 25



2 F1 F2 C X D S E W 3 2





7 R95

8 L95




12 F9 F10 / ' ; [ P - 0 F11

13 F7 F8 . , L K O I 9 8

14 F5 F6 M N J H U Y 7 6

15 F3 F4 B V G F T R 5 4

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