Samsung RL44Q Series Service Manual page 189

5. SELF DIAGNOSIS & TROUBLE SHOOTING REFERENCE INFORMATION
9-3-2-4) Reset Circuit Part
1) When the MICOM is on or re-energized after momentary interruption, the reset circuit initialize
several parts in MICOM such as RAM in order that the whole program can be operated from
the initial stage. On impression, comparing the Vcc(5VDC) of MICOM, the voltage across the
reset terminal becomes "LOW" for several tens seconds and in normal operation, the voltage
maintains "HIGH" (Vcc voltage) state.
9-3-2-5) The circuit for sensing the door switch
* DOOR SW & MICOM STATE
DOOR CORE
CLOSE LOW
OPEN HIGE
1) The door position of the refrigerator is detected by Vcc(5VDC) supplied to
R401 and the contact of the door switch is connected to Gnd. As the contact is connected to
Gnd according to the position of the door, "HIGH"(5V) or "LOW"(0V) signal is sent to the
MICOM. MICOM detects the open/close position of the refrigerator door with this voltage
change.
Note) If the door switch has a fault, the damper in the refrigerator compartment can be
incorrectly operated or the alarm function is initiated. The door switch should be checked
on after-sales service. If the door opens, the damper in the refrigerator compartment is
closed, but on fault, even though the door is closed, MICOM judges the door open and
closes the damper.
Terminal
F
compartment
Voltage
Door Closed
Door Open
189
Terminal
Vcc (IN)
Reset (OUT)
MICOM MICOM PIN Number
0V(LOW)
5V(HIGH)
Voltage
DC 5V
DC 5V
⑤ of CN30 through
Number 49 or
⑤
of CN30