Toshiba 22031020002961, Service Manual

Page: 38 / 51

Service Manual , 2017-8
38 / 51
The characteristic that resistance value reduces as the temperature increases is deemed to have
negative slope or negative temperature coefficient (NTC), and such thermistor is called as NTC
thermistor. The resistance value changes sensitively with temperature and typically changes 7% ~
3% per degree centigrade. Sensor used in the refrigerator is NTC thermistor.
There is following computing formula for the sensor:
Sampling voltage / reference voltage = R1 / (RNTC + R1)
AD value / reference AD value = R1 / (RNTC + R1)
The reference voltage is 5V, RNTC is the resistance value of the sensor, R1 is R31\R32\R33 in
schematic diagram that is 5.1K
10.4 Fan motor circuit of the freezing chamber
The fan in the freezing chamber is running when the compressor is operating. Check 12V and
FAN to see if there is a voltage of 12V. When in normal operation, the fan is in low level and the
voltage between 12V and FAN is more than 11V. If theres no voltage when the compressor is in