msl5864@ritcv.UUCP (03/13/87)
I just bought a couple of Atari brand trackballs at the local hobby store
for 14 bucks and decided to convert one of them to work like a mouse for
my Amiga. I followed the instructions that were given a while back for Atari
trackballs, and totally ruined the thing. After working on a second one, I
studied the circuits myself and have successfully made the modification.
The first part of the modification is quite easy and doesn't need any soldering.
THe second part will involve a minor amount of soldering and that is so that
the right switch can be disconnected from the left and work like the mouse.
Part I. Open the trackball by removing the screws and prying the two halves
apart. There will be a 6 pin connector at the end of the DB-9 cable. Scratch
away the foil paths on the circuit board that lead to pins 1 through 4 from
left to right. (Two of the foil paths are on one side of the circuit board
and the other two are on the other side). Connect the following pins
from the 6 pin connector to the pins of the LM339.
6 PIN CONNECTOR LM399
--------------- -----
1 -> 14
2 -> 2
3 -> 13
4 -> 1
I accomplished this by piggy backing a second socket on top of the LM339 and
just plugging wires from the connector to the socket. This should complete
part I. To test it out, plug it in to the Amiga and try to use it like a
mouse. Both buttons will work like the left button on the mouse.
Part II. In order to make the right button work like the right button on the
mouse you will have to buy another cable. In the trackball I bought, there was
no wire for pin nine of the DB-9 connector and that is where the right switch
goes. So, cut off the old cable and solder the remains of the old cable to the
new cable. Cut the red wire connecting the two switches so that the majority
of the length is attached to the right switch. COnnect the wire from the right
switch to pin nine of the cable. Now the trackball should work just like a
mouse. Be very careful that you don't connect the wrong wires from the DB-9
cable to the six pin connector and switches. On my first attempt I switched
pins 7 and 8 by accident and blew some of the chips on the circuit board.
I have already built this circuit and I don't believe there are any mistakes
in this posting. I am sorry in advance for any mistakes there might be. Also,
I have nothing to do with Commodore or Atari.msl5864@ritcv.UUCP (03/13/87)
Whoops, on my last posting, the machine didn't include my .signature.
Michael S. Leibow
UUCP: {allegra,seismo}!rochester!ritcv!msl5864
CSNET: msl5864%rit@csnet-relay.ARPA