Mac Plus - No mouse cursor movement

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Hungry Computer's picture
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Mac Plus - No mouse cursor movement

Hi all,


I'm having mouse problems with a Mac Plus, and I would appreciate any help. I have 2 M0100 mice, and with both mice it registers clicks but no movement. Even removing the ball and manually spinning the rollers doesn't register anything. I don't know for sure if the mice or Plus were working properly before I got them. Here's the testing I've done so far:



  • Confirmed that the IR LEDs are working.
  • Confirmed continuity between optical sensors and microchip.
  • Confirmed continuity from output pins to end of cable.


Mac Plus

  • Looked over analog board, no obvious issues. None of the capacitors are bulging or leaking, etc.
  • Pulled the motherboard, plugged in mouse, and confirmed continutity between the output pins of the mouse's board to the mouse port's solder points.
  • Reseated RAM (4MB)


I think I can rule out connection issues, but I don't have another system to properly test the mice with. Just an Apple IIe with no mouse card. I tried plugging them into the IIe's game port anyway, and a few programs do register up-down mouse movement as an erratic joystick y-axis. So I'm guessing that the issue is somewhere on the Plus' motherboard. 


Is there anything else I should test on the mice or Plus?