LG GR-349SQF Service Manual ▷ View online
4) LOAD/BUZZER OPERATION, DOOR OPENING SENSING CIRCUIT
(1) LOAD OPERATION CHECK
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If the DOOR-R is opened during FAN MOTOR is operated, FAN MOTOR is stopped immediately.
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The A , B of DOOR S/W-R is connected DOOR OPEN DETECTION CIRCUIT as follow.
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If the DOOR-R is opened or closed, then the DOOR S/W-R is ON/OFF, and the LAMP-R is ON/OFF,
and at the same time, S/W of the A , B of DOOR S/W-R for detection of DOOR-R open is ON/OFF.
and at the same time, S/W of the A , B of DOOR S/W-R for detection of DOOR-R open is ON/OFF.
(2) DOOR OPENING PERCEPTION CHECK
*NOTICE: If you would change DOOR S/W-R, must use the componenot of right PART NUMBER. Because there is a
similar type DOOR S/W-R of NOT MICOM MODEL, it's logic of the A , B of DOOR S/W-R is reversed.
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Even though LAMP-R is operated a normal ON/OFF according to DOOR S/W-R, but the MICOM couldn't detect a
DOOR-R opened or closed of lead wire of the A , B is abnormal or S/W of the A , B of DOOR S/W-R is abnormal.
DOOR-R opened or closed of lead wire of the A , B is abnormal or S/W of the A , B of DOOR S/W-R is abnormal.
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When DOOR-R open isn't detected : Even though DOOR-R is opened, FAN MOTOR couldn't stop.
When DOOR-R close isn't detected : Even though DOOR-R is closed, BUZZER sounds a DOOR OPEN ALARM.
check a lead wire of the A , B and DOOR S/W-R.
When DOOR-R close isn't detected : Even though DOOR-R is closed, BUZZER sounds a DOOR OPEN ALARM.
check a lead wire of the A , B and DOOR S/W-R.
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KIND OF LOAD
COMP,
FAN MOTOR
DEFROSTING HEATER
COMP COOLING FAN
MEASURING POINT (IC5)
No.13
No.14
No.15
ON
below 1V
STATE
OFF
12V
MEASURING POINT
NO.6 OF IC 1 (MICOM)
REFRIGERATOR DOOR
CLOSE
5V(S/W of A , B is OFF state)
OPEN
0V(S/W of A , B is ON state)
(3)BUZZER OPERATION CHECK
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DISPLAY FUNCTION BUTTON RING
DOOR OPEN ALARM
(DING~ DONG~)
(SCREECHING)
OFF
IC1 (No.14 Pin)
ov
IC1 (No.13 Pin)
ov
MEASURING
POINT
POINT
CONDITIONS
0.05s
0.2s
0.1s
1s
0V
5V
0V
5V
0V
5V
0V
5V
0.5s
0.5s
2.66kh
z (DING~)
2.232kh
z (DONG~)
3.1kh
z
OFF
5) TEMP SENSOR CIRCUITS
The above circuit reads the surrounding temperature, DEFROSTING temperature and FREEZER ROOM temperature into
MICOM(IC1). OPEN or SHORT state of each SENSOR is as follows.
MICOM(IC1). OPEN or SHORT state of each SENSOR is as follows.
6) SWITCH INPUT CIRCUIT
The following circuit is a test switch input circuit for checking the refrigerator.
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(RT– SENSOR)
(DEFROST SENSOR)
(FREEZER COMPARTMENT
SENSOR)
SENSOR)
SENSOR
CHECK POINT
NORMAL (-30
°
C~50
°
C)
SHORT
OPEN
ROOM TEMPERATURE
SENSOR
POINT A Voltage
DEFROST SENSOR
POINT B Voltage
0.5V ~ 4.5V
0V
5V
FREEZER SENSOR
POINT C Voltage
7) TEMPERATURE COMPENSATION
• TEMPERATURE COMPENSATION TABLE by adjusting resistance values. (the temp difference compared to the present
temp.)
eg) If the compensation resistance of freezer compartment is changed from 10K (present resistance) to 18K (revised
resistance), the temp of freezer compartment goes up by +2
°
C.
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FREEZER TEMPERATURE
COMPENSATION
FREEZER ROOM
RESISTANCE VALUES(R1)
TEMPERATURE COMPENSATION
REMARKS
180 k
Ω
+ 5.0
°
C
COMPENSATE WARMLY
56 k
Ω
+4.0
°
C
33 k
Ω
+3.0
°
C
18 k
Ω
+2.0
°
C
12 k
Ω
+1.0
°
C
10 k
Ω
0
°
C
STANDARD
8.2 k
Ω
-1.0
°
C
5.6 k
Ω
-2.0
°
C
3.3 k
Ω
-3.0
°
C
2 k
Ω
-4.0
°
C
470
Ω
-5.0
°
C
COMPENSATE COOLLY
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