My wife has a very expensive sewing machine that uses a trackball for some of it's function selection. However the vertical track does not work (horizontal does work). I took it apart and it looks like the inside of computer mouse. Does anyone know how the sensor works and translate axle movement to electrical an impulse? Light, magnetic....doesn't look like a variable resistor. And suggestions on fixing....thanks!
PS How is a "Semi" sealed" LED case back lit? Is there a bulb in the casing?
