LG GR-B197DVCA, Service Manual

Page: 37 / 119

3. Door opening sensing circuit
✽
Since door switch sensing switch (A), (B) are a separate switch even if the door switch of the freezing room normally
operates, they may fail to sense door opening in the failure of switch at both ends of (A) and (B) or in failure of the L/wire.
✽
Lamp does at the cold storage room not turn on if the door switch of the cold storage room fails to sense the door open
switch (c ), (d) or the home bar switch.
EXPLATION FOR MICOM CIRCUIT
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Closing 5 V ( A - B , C - D . S/W at both ends are at Off status)
Opening 5 V ( A - B , C - D . S/W at both ends are at On status)
Measuring part
IC1 (MICOM) No. 47, 46 Pin
Door of Freezing/Cold Storage Room
<GR-L207, GR-L247> <GR-B197, GR-B207, GR-B247>
<GR-L207, GR-L247> <GR-B197, GR-B207, GR-B247>
CONDITIONS
Bell sounds when button on Beep sounds when warning
MEASURING
dosplay is pressed. door opening.
OFF
POINTS
IC1 (No. 48 Pin) 5 V
IC1 (No. 51 Pin) 0 V
0.05 s
2.63 kz (DING)
2.63 kz (BEEP) OFF
2.21 kz (DONG)
0.2 s 0.1 s 0.4 s 0.5 s 0.5 s
5 V
0 V
5 V
0 V
5 V
0 V
5 V
0 V