jdeitch@umiami.ir.miami.edu (Jonathan Deitch) (03/26/91)
Ok, for all those who are interested (so my mailbox will cool off, whew !)
here are instructions for converting an Atari Trackball for use on an Apple
//c or //e with a mousecard.
Materials needed :
- Atari Trackball CX-80 ($4.97 at KayBee Toys)
- 9 pin male D type connector \
- Hood for above |
- (1) 74LS04 (TTL hex inverter chip) |
- 14 pin socket for above |-- Avail. at Radio Shack
- some small guage wire |
- soldering iron |
- wire strippers /
Here we go :
- cut the plug off the end of the trackball's cord as near to the plug as you
can. Now strip about .75" of the outer insulation to expose the colored
wires inside. Strip a little bit from the end of each wire so you can
solder the ends to the terminals of the 9 pin connector.
- Solder the colored wires to the terminals of the 9 pin connector as so :
pin 1 : solder this to pin 3 (the grey wire)
pin 2 : Purple
pin 3 : Grey (this must also be soldered to pin 1)
pin 4 : Brown
pin 5 : Red
pin 6 : unconnected
pin 7 : Blue
pin 8 : Orange
pin 9 : Yellow
Make sure none of the pins are shorting another and then put the hood on the
connector.
- Now carefully peel each of the four rubber feet off of the bottom of the
trackball case to expose the screws. Make sure you put the feet gummy side
up in a safe place where they won't become stuck to anything.
- Now unscrew the screws (small phillips head screwdriver) and lift the top
of the case off the bottom.
- carefully snip the wire off of the yellow, orange, and red wires as close
to the metal connector as possible.
- Solder extra wire to each of the three connectors you just cut the colored
wire from. Note that each connector is labeled by its color on the circuit
board. These will be referred to as <color> connector while the wires
themselves will be referred to as <color> wire.
- Connect the yellow connector to pin 11 of the 74LS04.
- Connect pins 9 and 10 of the 74LS04 together.
- Connect the yellow wire to pin 8 of the 74LS04.
- Connect the orange connector to pin 13 of the 74LS04.
- Connect the orange wire to pin 12 of the 74LS04.
- Connect the red connector to pin 3 of the 74LS04.
- Connect pins 4 and 5 of the 74LS04.
- Connect the red wire to pin 6 of the 74LS04.
- Looking at the circuit board of the trackball with the connectors facing
you, solder a wire to the solder pad immediately to the right of "A2010"
right behind the blue and violet connectors. Using an ohmmeter, this pad
should be connected to the violet connecter. This is the +5 volt supply.
Now solder the other end of the wire to pin 14 of the 74LS04. Check chart
below if you need help finding the +5 volt pad.
____________________
\
_____________________O <-- solder to this pad for +5
\
\
_____________________O \ <-- don't solder to this pad
| |
| |
| |
| |
[ ] [ ] [ ]
grey blue violet
- Now, looking at the left edge of the circuit board, there is a foil pattern
along the left edge of the board. Right above the crosshatch pattern in
the lower lefthand corner is a single solder pad. Solder a wire to this.
Now solder the other end of the wire to pin 7 of the 74LS04. This is the
ground connection. See chart below if you are having problems :
|
|
|-------O <-- solder to this solder pad
|
|---------
| ----------|
|--------- |-------
| ----------|
|---------
|
|________________________
- This should be all the electrical connections needed.
- I found that the best place to stuff the chip and its wires is under the
righthand edge of the board right under the cross hatch pattern in the
lower righthand corner. This places it between the housing for the TB/JS
switch and the plastic support for the circuit board where it should wander
and interfere with any of the mechanisms.
- Once this is done, plug it in and see if it works. If it does, put the
cover on and have fun. If it doesn't, check all connections. When I first
put this together, I accidently solder the +5 for the 74LS04 to the solder
that is closer to the blue and violet connectors. This happens to be the
circuit for the buttons and whenever I pressed the buttons this line went
low and shut off the 74LS04 thus stopping all input to the computer !!
BE CAREFUL !! -- Shorts can damage your mouse interface !!!
Here's a logic diagram :
Connector Wire Function
---------- ---- --------
|-\ |-\
Yellow ----| >O----| >O-----------Yellow Vert. Mvmt. Pulse
|-/ |-/
|-\
Orange -------------| >O-----------Orange Vert. Direction
|-/
|-\ |-\
Red ----| >O----| >O-----------Red Horiz. Mvmt. Pulse
|-/ |-/ up
Brown -----------------------------Brown Horiz. Direction
Violet -----------------------------Violet +5 VDC
Blue -----------------------------Blue Buttons (HI=up,LOW=dn)
Grey -----------------------------Grey Logic Ground
|-\
| >O is 1/6 of the 74LS04 hex inverter. The Yellow and Red are run through
|-/ two gates so that they are buffered. The Orange needed to be
inverted so it only goes through one gate. One gate is unused.
If anyone has any troubles, feel free to e-mail me but make sure to inlcude
the words "Trackball" and "Problems" in the subject line as I have been
getting *LOTS* of mail about this.
Have fun !!!!!!
Non computer communications :
Ma Bell : 1-305-284-6482
US Snail : Jonathan Deitch
1231 Dickinson Drive #1007W
Coral Gables, FL 33146 USA
'til later ...
- Jonathan
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Internet : jdeitch@umiami.miami.edu | "Good musicians execute
------------------------------------------------- | their music but bad ones
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