LG LRG3061ST Service Manual page 64

CHECKING FLOW CHART BY FAILURE
Oven lamp does not operate
Check the oven lamp (measure the resistance)
Normal:approximately 20~40Ω, Abnormal : infinite
NO
COM
Normal?
Yes
Replace the power PCB
Normal?
Yes
END
No
No
10-18
Abnormal
Infinite
Replace the oven lamp
END
Replace the main PCB
END