Service manual

18
R-1855A
MAGNETRON POWER TRANSFORMER H.V. RECTIFIER HIGH VOLTAGE CAPACITOR SEC. INTERLOCK AND DOOR SEN. SWITCH PRIMARY INTERLOCK SYSTEM MONITOR SWITCH DAMPER SWITCH MONITOR FUSE TEMPERATURE FUSE (MG) HOOD THERMAL CUT-OUT THERMISTOR
TROUBLESHOOTING GUIDE
When troubleshooting the microwave oven, it is helpful to follow the Sequence of Operation in performing the checks. Many
of the possible causes of trouble will require that a specific test be performed. These tests are given a procedure letter which
will be found in the "Test Procedure" section.
CK = Check / RE = Replace
CONDITION
TEST PROCEDURE
POSSIBLE CAUSE
AND
DEFECTIVE PARTS
ABCDEFGHI JK L
OFF
CONDITION
IDLE
CONDITION
COOKING
CONDITION
(COMMON)
PROBLEM
Home fuse blows when power cord is plugged into wall receptacle.
Monitor fuse blows when power cord is plugged into wall receptacle.
Display does not illuminate when power cord is first plugged into wall recepta-
cle.
Display does not operate properly when STOP/CLEAR key is touched. (The
time of day should appear on the display with beep sound during normal
condition.)
Oven lamp does not light with door is opened.
Hood fan motor operates when power cord is first plugged into wall receptacle.
Temperature of oven base seems more than 140½F (60½C) because of operation
of the range below. But hood fan motor does not turn on automatically.
(Normally, food fan motor should be operating at low speed.)
Hood lights do not turn on with pushed HOOD LAMP button.
Hood fan motor does not rotate at all with pushed FAN button.
Speed of the hood fan motor does not change when the FAN button is touched
for this function.
Oven lamp does not light in cook cycle. (But it does light when door is opened.)
Fan motor does not operate. (Oven lamp and turntable motor operate.)
Turntable motor does not operate (Oven lamp lights and fan motor operate.)
Cooking cycle runs 1 minute then shuts down.
Oven does not go into cook cycle when START pad is touched
Oven seems to be operating but little or no heat is produced in oven load. (Food
incompletely cooked or not cooked at all at end of cook cycle.)
Oven goes into a cook cycle but extremely uneven heating is produced in oven
load (food).
Variable cooking does not operate properly except Cooking Power 10 (P-HI)
mode.
Function of COMPU DEFROST does not operate properly.
Stirrer motor does not operate. (Other parts operate.)
CONV indicator lights, but oven does not go into cook cycle when START pad
is touched.
CONV indicator lights, but heating element does not heat.
Temperature in the oven cavity is lower or higher than preset.
Convection motor does not operate.
Convection cycle runs 4 minutes and 15 seconds then shuts down.
The oven stops and "ERROR" is displayed or does not end during Sensor
Cooking condition. (Oven does not shuts off after a cup of water is boiling by
Sensor Cooking.)
Oven stops at 32 seconds after starting.
MICROWAVE
COOKING
CONDITION
CONVECTION
COOKING
CONDITION
SENSOR
COOKING
CONDITION