(2) CHECKOUT PROCEDURES FOR RELAY.

- PROBLEM (A) -

FAN motor and oven lamp turn on without touching

START key when the door is closed.

NO

YES

GOOD

Remove the mate connector of I/O CON from the circuit board.

Does the unit still operate?

NO

YES

Replace the circuit board

Defective

RELAY1

Replace

RELAY1

- PROBLEM (B) -

FAN motor and oven lamp turn on When the door is closed and START key is touched.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

YES

 

 

 

 

 

 

NO

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

GOOD

Measure the voltage at pin NO.

35 of U01

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Voltage reading: 0 Vdc

 

 

 

 

10 of U03

 

 

 

 

 

 

 

 

 

 

Voltage reading: about 15V

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

NO

 

 

 

 

 

YES

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Replace the circuit board

Defective

RELAY1 or poor

connection of

RELAY1

Replace

RELAY1 or correct

the connection.

7-19

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Image 30
LG Electronics LMV1825SBQ, MV1825SW service manual Checkout Procedures for Relay Problem a