LG GR-B-L207EC-ER Service Manual ▷ View online
2. GR-C247, GR-C207, GR-B247, GR-B207
MICOM CIRCUIT DESCRIPTION
- 50 -
Refrigerator Compartment
Temperature Compensation
Temperature Compensation
Freezer Compartment
Temperature Compensation
Temperature Compensation
MICOM CIRCUIT DESCRIPTION
- 51 -
Freezer
Temp
Control
Temp
Control
Refrigerator
Temp
Control
Temp
Control
1. Description of PWB Circuit
1-1. Power Circuit
1. GR-P247, GR-P207, GR-L247, GR-L207
Power circuit is composed of switching mode power supply (SMPS) electric parts. SMPS is composed of rectifying part
(D1~D4, CE1) which converts AC to DC voltage, switching part (IC2) which switches this converted DC voltage, trans which
transmits primary energy to secondary energy, secondary power source which transmits power to MICOM and IC, and feed
back part (IC3, ZD1) which feeds back voltage to primary trans in order to maintain constant secondary voltage.
The voltages at each part are as follows.
(D1~D4, CE1) which converts AC to DC voltage, switching part (IC2) which switches this converted DC voltage, trans which
transmits primary energy to secondary energy, secondary power source which transmits power to MICOM and IC, and feed
back part (IC3, ZD1) which feeds back voltage to primary trans in order to maintain constant secondary voltage.
The voltages at each part are as follows.
Note : If circuit is abnormal, repair it after 3 minutes when power cord is unplugged. Be care of electric shock as high
voltage (DC 310 V) is applied to the circuit.
2. GR-C247, GR-C207, GR-B247, GR-B207
In the trans secondary side is composed of power source (12 Vdc) for driving relay and power source (5 Vdc) which supplies
power to MICOM and IC. Voltages in each part are as follows.
power to MICOM and IC. Voltages in each part are as follows.
1-2. Oscillation Circuit
This is to generate basic time for synchronous clock and time calculation for
internal logic element to send and receive information.Standard parts should be
used as the time calculated by IC1 shall be changed or shall not work if OSC1
specification is changed.
internal logic element to send and receive information.Standard parts should be
used as the time calculated by IC1 shall be changed or shall not work if OSC1
specification is changed.
1-3. Reset Circuit
Reset circuit is to initialize RAM in MICOM (IC1) and make all functions
to start from the initial conditions when power is nitially applied or
power is reapplied to MICOM after power cut. Low voltage is applied for
10 ms to the reset terminal of MICOM when power is applied. 5 voltage
is applied to the reset terminal for general operation. (MICOM does not
to start from the initial conditions when power is nitially applied or
power is reapplied to MICOM after power cut. Low voltage is applied for
10 ms to the reset terminal of MICOM when power is applied. 5 voltage
is applied to the reset terminal for general operation. (MICOM does not
work when IC9(Reset IC) is failed)
MICOM CIRCUIT DESCRIPTION
- 31 -
Position
VA1
CM1
CM2
CE2
CE4
Voltage
220 Vac
14 Vac
17 Vac
12 Vdc
5 Vdc
2. Refrigerator Weak Cooling and Over Cooling Compensation Circuit
• The above option circuit is to compensate the refrigerator compartment temperature by cutting during service.
MICOM CIRCUIT DESCRIPTION
- 40 -
WEAK COOLING
OVER COOLING
COMPENSATION
COMPENSATION
REFRIGERATOR COMPARTMENT
REMARKS
JCR3
JCR4
JCR1
JCR2
TEMPERATURE COMPENSATION
0
°
C (FACTORY SHIPPING)
CUT
-1
°
C
CUT
-1
°
C
CUT
+1
°
C
CUT
+1
°
C
CUT
CUT
-2
°
C
CUT
CUT
+2
°
C
CUT
CUT
0
°
C
CUT
CUT
0
°
C
CUT
CUT
0
°
C
CUT
CUT
0
°
C
CUT
CUT
CUT
-1
°
C
CUT
CUT
CUT
+1
°
C
CUT
CUT
CUT
CUT
0
°
C
Temperature Compensation by Cutting
JCR1
+1
¡
+2
¡
JCR2
+1
¡
JCR3
-1
¡
-2
¡
JCR4
-1
¡
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