Damper Motor Drive Part - Samsung RS20NCSL Service Manual

10-9. Damper motor drive part

● Movement description
Damper is a 2 excitation type stepping motor used in controlling the refrigerator temperature. It is opened
when the temperature is higher than the setting temperature of refrigerator sensor, and closed lower
according to the refrigerator notch.
It performs a open/close without regardless of refrigerator temperature at power ON, and then decides the
state of open/close according to the temperature.
Open/close action is controlled by MICOM #34, #35, #37 through damper motor(stepping-motor) exclusive
control drive IC(IC8:TA7774P).
Damper heater is supplied DC12V whenever voltage impresses to the refrigerator and the signal is occurred
always in MICOM #24, DC 12V flows into
the damper heater by IC3.
※ Note
In case of the above damper heater, because the PCB cannot detect the open/close state, there is no self
diagnosis function for deciding the abnormality. IN the above diagram, if a wire cut off linked 3,4,5 of CN7,
motor is run as a normal, but refrigerator over cooling occurs by slightly open at the
close of damper.
So, check for deciding of abnormality of damper motor connection part like followings.
1) Check method : After separation of CN72 housing, measure the resistance value by use of
multi tester and decide the abnormality.
2) Resistance value spec
①-② (black, brown) : 150Ω±15%
③-④ (white, blue) : 426Ω±15%
⑤-⑥ (yellow, red) : 426Ω±15%
32