Samsung RS277ACPN Manual page 82

5. Circuit Descriptions
5-12. CoolSelect Zone Panel Circuit
2) Damper drive circuit
2-1) CoolSelet Zone Drawer is controlled by a damper to supply or block cold air. For
Quick Cool, the damper will be close. So cold air is supplied only to CoolSelect
Zone Drawer. For Thaw, the evaporator heater of refrigerator is ON and the
damper is controlled by the refrigerator temperature.
2-2) The stepping motor controlled by a Driver IC TA7774P(IC8) operates the damper.
The stepping motor uses 4 combined signals to open and close the damper.
Note To prevent the malfuntion from a high humidity, a DC12V, 1W heater is
mounted and activated continuously.
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