AD Pins

Are all pins capable of adc?

no, please see brochure for the analog pins. Of course I do not know which product your talking about.

g120…i think i found out…is see there are pins AD1-AD7 which are the ADC pins

Looking at the analog input example i should be able to use lightSensor.SetLinearScale(0, 100); but it is not recognised

    using System.Threading;
    using Microsoft.SPOT;
    using Microsoft.SPOT.Hardware;
    namespace change_this_to_your_namespace
       public class Program
          public static void Main()
             AnalogInput lightSensor = new AnalogInput((Cpu.AnalogChannel)Cpu.AnalogChannel.ANALOG_7);
             double lightSensorReading = 0;
             while (true)
                 lightSensor.SetLinearScale(0, 100); //method not recognised
                lightSensorReading = lightSensor.Read();

That is an old 4.1 API
Check this thread: