LG GR-349SQF Service Manual ▷ View online
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2 FUNCTION DESCRIPTION
1) ELECTRIC CIRCUITS
TRANS secondary side is composed of electric power circuits for RELAY driving electricity (12Vdc) and for supplying
electricity to MICOM and IC (5Vdc). The voltage in each part is as follows.
electricity to MICOM and IC (5Vdc). The voltage in each part is as follows.
VA1 is the part to protect over voltage and noise. When more than 385V is applied, the thermal-fuse(130
°
C cut-off, local
option) in a first part of TRANS is cut so that the elements in the secondary side of TRANS are protected.
2) OSCILLATION CIRCUIT
CIRCUIT for occurring CLOCK which motivates the internal local element of IC1 to transmit and receive an information and
BASIC TIME for calculating time. Use a proper form for OSC 1. Because in case that SPECIFICATION is changed, the
calculated time in IC1 is changed or IC1 isn't able to operate.
BASIC TIME for calculating time. Use a proper form for OSC 1. Because in case that SPECIFICATION is changed, the
calculated time in IC1 is changed or IC1 isn't able to operate.
3) RESET CIRCUIT
All the internal parts of MICOM(IC1) return to the initial condition when the early power ON or apply power again in MICOM
after temporary power failure. As a result, all the functions operate acording to the early condition. At the early period of
power ON the "LOW" voltage is applied in the RESET terminal of MICOM for the fixed time. The RESET terminal is 5V
during the general operation.
after temporary power failure. As a result, all the functions operate acording to the early condition. At the early period of
power ON the "LOW" voltage is applied in the RESET terminal of MICOM for the fixed time. The RESET terminal is 5V
during the general operation.
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PARTS
both ends of VA1
both ends of CM1
both ends of CM2
both ends of CE2
both ends of CC2
VOLTAGE
230Vac
14Vac
17Vdc
12Vdc
5Vdc
4) LOAD/BUZZER OPERATION, DOOR OPENING SENSING CIRCUIT
(1) LOAD OPERATION CHECK
ƒU
If the DOOR-R is opened during FAN MOTOR is operated, FAN MOTOR is stopped immediately.
ƒU
The A , B of DOOR S/W-R is connected DOOR OPEN DETECTION CIRCUIT as follow.
ƒU
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.
ƒU
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.
ƒU
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
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