How to make the right mouse button of the STM1 (Atari ST Mouse) work on the 8 bit Atari. I upgraded my own ST mouse (I specially bought an ST mouse for my 8 bit Atari) years ago using an article in ABBUC Magazines 35 and 38, which was published twice, by Markus Witte. Here's how I upgraded my mouse. It's slightly different from what Markus did, but I think it's easier. What should you know before your start this upgrade: - Your mouse will still work on an ST after this upgrade. - There are at least 8 or 9 different ST mice. - Atari PC Mice look the same (except that they are white instead of grey), but are totally different inside. The only parts you might interchange are the housing and the screws. Even the cable is different. - There are few things Atari ever made with a lower quality then their mouse cables. Just looking at them can break them. If you have to replace one, make sure you have the right cable!!! - If you know which side of a screwdriver to hold (screwdriver as in 'tool', not as in 'drink'), you can do this upgrade. - Don't drop you mouse. They break. I know. - Read this file from top to bottom BEFORE you start. - If you damage something, that's your problem. Roll up your sleaves. Turn over the mouse. Remove the ball and make sure to put it somewhere where it'll stay. Round things have a tendency to roll. If you don't want to crawl around under your desk, put it somewhere save. Remove the screws. Both of them. The top will tilt toward the opposite side of where the screws were. The cable should stay with the bottom halve. Look at where the cable is connected to the printed circuit board. See the connector on the cable and how the wires from the cable disappear into the connector? Take a resistor of 4.7 KiloOhm or 5.6 KiloOhm. Stick one leg into the hole where the red wires is and the other one where the white one is. Enter the following into your computer: 10 ? PADDLE(0):GOTO 10 or 10 ? PADDLE(2):GOTO 10 Depending on which joystickport your using and RUN it. If the right button isn't pressed, a value of 228 will be returned. If it is pressed, a value lower then 9 should be returned. If the value stays at 228 check to see that the resistor is connected between pins 7 and 9. If the value is to high, use a different resistor. If everything works, cut the legs of the resistor to size so that the resistor will fit inside both connector and mouse making sure that the resistor will not fall out. Close up the mouse. HAVE FUN!!! Mathy van Nisselroy