LG Gr P227 Ytqa Service Manual

1-6. Switch entry circuit
The following circuits are entry circuits for sensing signal form test S/W, electronic single motor damper reed S/W for
examining refrigerator.
1-7. Option designation circuit (model separation function)
The above circuits are used for designating separation by model as option and notifying it to MICOM. Designation of option
by model and the application standards are as follows:
uThese circuits are accurately pre-adjusted in shipment from factory and so you must not additionally...

1-8. Stepping motor operation circuit
EXPLATION FOR MICOM CIRCUIT 
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For motor driving method, rotation magnetism is formed at coils wound on each phase of motor and stator and so motor
becomes to rotate if applying “High” signal to the IC8 (TA777AF) at the MICOM PIN 33 and outputting “High”, “Low” signal
by step numbers fixed through MICOM PIN 34 and 35,.
Explanation) For driving method of the stepping motor, send signals in the cycle of 3.33 mSEC using terminal of MICOM
PIN 33, 34 and 35 as shown in wave form of the following part. 
These signals are output to the...

1-9. Fan motor driving circuit (freezing room, M/C room)
1. This circuit performs function to make standby power ‘0’ by cutting off power supplied to ICs inside of the fan motor in the
fan motor OFF.
2. This is a circuit to perform a temporary change of speed for the fan motor and applies DC voltage up to 7.5V ~ 16V to
motor.
3. This circuit performs function not to drive the fan motor further by cutting off power applied to the fan motor in the lock of
fan motor by sensing the operation RPM of the fan...

EXPLATION FOR MICOM CIRCUIT 
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b
a
e
d
 

EXPLATION FOR MICOM CIRCUIT 
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b
a
e
d
b
a
e
d
 

1-10. Temperature compensation and over-cool/weak-cool compensation circuit
1. Temperature compensation at freezing room, cold storage room 
EXPLATION FOR MICOM CIRCUIT 
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EXPLATION FOR MICOM CIRCUIT 
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uTemperature compensation table by adjustment value (difference value against current temperature) 
Ex) If changing compensation resistance at a cold storage room (RCR1) from 10 kΩ(current resistance) to 18 kΩ
(modified resistance), temperature at the cold storage will increase by +1°C. 
Ex) Now (R)J1=           , (R)J2=1.2kΩ, RCRI=5.6kΩwant to compensate -2°C for Freezing room temperature and
+2°C for Cold storage room temperature
(R)J1 = 12kΩ1kΩ
(R)J2 = 12kΩ
RCRI =...

uTemperature compensation table at the cold storage room is as follows:
uThis circuit is a circuit to enter the necessary level of temperature compensation for adjusting different temperature every
model at the cold storage room into MICOM.
EXPLATION FOR MICOM CIRCUIT 
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470 Ω2 kΩ3.3 kΩ5.6 kΩ8.2 kΩ10 kΩ12 kΩ18 kΩ33 kΩ56 kΩ180 kΩ
No 0.5 °C1 °C 1.5 °C2 °C 2.5 °C3 °C 3.5 °C4 °C 4.5 °C5 °C
470Ω
changeUp Up Up Up Up Up Up Up Up Up
0.5 °C No 0.5 °C1 °C 1.5 °C2 °C 2.5 °C3 °C 3.5 °C4 °C 4.5 °C
2 kΩ
Down...

1-11. Display Circuit
EXPLATION FOR MICOM CIRCUIT 
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