Sears 721.88502800 Manual page 46

Complete the following steps before checking microwave circuitry:
1. Check the line voltage, household fuse or circuit breaker.
2. Check for loose wiring or mis-wiring within microwave.
3. Disconnect white wire from high-voltage transformer and discharge high-voltage capacitor.
NOTE: 1. All testing must be done with an ohmmeter having a sensitivity of 20,000 ohm per volt
or greater and powered by at least a 9-volt battery.
2. All operational checks with microwave energy must be done with a load
(1 liter water in a measuring glass cup) in the microwave oven.
N
1. UNIT IS PLUGGED IN
CN2
WH WH/WH
CLOCK DISPLAY ON.
3
OVEN TCO
OVEN LAMP
N
2. MICROWAVE
CN2
WH WH/WH
COOKING ON
3
RY 1
OVEN TCO
TT MOTOR
N
CN2
WH WH/WH
3
RY 1
OVEN TCO
FAN MOTOR
N
CN2
WH WH/WH
3
RY 2
OVEN TCO
PRIMARY OF H.V.T
N
WH WH/WH
RY 10
OVEN TCO PRIMARY
COIL OF H.V.T
N
3. VENTOR MOTOR ON
CN2
WH WH/WH
3
RY 8
OVEN TCO
N
4. COOKTOP LAMP
CN2
WH WH/WH
ON 3
RY 6
OVEN TCO
NOTE: As low voltage transformer is energized, relays will close and complete circuit.
10-7
L
CN2
POWER
BL/BL/BK BK BK
TRANS 1
MGT TCO FUSE 20A
L
CN2
BK BK BK
5 O.L
MGT TCO
FUSE 20A
L
CN2
RD/RD/RD BK BK BK
5
T.T.M
PRIMARY MGT FUSE
SW TCO 20A
L
CN2
RD BK BK BK
7 F.M
BN
PRIMARY MGT
FUSE
SW TCO 20A
YL
S.M
L
BN RD BK BK BK
RY 9 PRIMARY MGT FUSE
SW TCO 20A
L
CN4
BK BL/BK BK BK
5 V.M
MGT TCO
FUSE 20A
L
CN4
BN BK/BK BK BK
3
C.L
MGT TCO FUSE 20A