LG MC-766YS Service Manual page 22

COMPONENTS
CIRCULATION MOTOR
(Wire leads removed)
NOTE:
*( ) = WIRE COLOR
RELAY 3, 4, OF P.C.B
(Disconnect the 9 pin
connector from P.C.B)
See Schematic Dagram on
page 4-3)
RELAY 2, 3, 4 OF P.C.B
(Wire leads removed.)
RY5 : Microwave
RY4 : Grill
RY6 : Convection
KEY PCB
NOTE : A MICROWAVE ENERGY LEAKAGE TEST MUST ALWAYS BE PERFORMED WHEN THE UNIT IS
SERVICED FOR ANY REASON.
MAKE SURE THE WIRE LEADS ARE CORRECT POSITION.
WHEN REMOVING THE WIRE LEAD FROM THE PARTS, BE SURE TO GRASP THE
CONNECTOR, NOT THE WIRES.
TEST PROCEDURE
Measure the resistance.
(Multi-meter scale : R x 1)
24V
(BN)
230V(BL)
COM
(YL)
1
CN2
3
5
7
9
Relay 3
Relay 4 Relay 5 Relay 6
Key P.C.B.
1
2
3
4
5
6
7
8
9
10
18
5-12
Normal : COM-230V : Approx. 150 Ω
Abnormal : Infinite or several ohm.
Cooking Start
Relay 4
Cooking Start
Check continuity between switch
Main P.C.B
terminals, by pressing an
1
appropriate pad on key board.
2
3
The contacts assignment of the
4
respective pads on the key board
5
6
is as shown left figures.
7
8
9
10
18
RESULTS
COM-24V : Approx. 20 Ω
OFF
OFF