STEP
SEQUENCE
RESUL
T
b
Resistance
OK
Replace control
circuit board.
(4) PROBLEM
Low microwave power
output.
a
Normal control
circuit board
Replace Blower
motor
∞
0
Resistance
incorrect
∞
274
Normal
Resistance
Replace thermal protector
for magnetron or thermal
protector for cavity
.
∞
0
∞
0
Defective H.V capacitor
,
H.V diode or H.V
. fuse.
Replace HV
capacitor
, H.V
diode or H.V
.
fuse.
Replace HV
Magnetron.
Runs
Runs
Runs
Runs
Runs
Runs
A
ut
o
St
ar
t
D
ef
.
Ti
m
e
A
ut
o
St
ar
t
D
ef
.
Ti
m
e
A
ut
o
St
ar
t
D
ef
.
Ti
m
e
A
ut
o
St
ar
t
D
ef
.
Ti
m
e
A
ut
o
St
ar
t
D
ef
.
Ti
m
e
A
ut
o
St
ar
t
D
ef
.
Ti
m
e
-11-
Normal Blower
Motor
Measure resistance
of blower motor
(Approx 274 ohms)
No
Operation
Normal thermal protector for
magnetron or thermal
protector for cavity
.
Normal
Operation
T
emporarily
short across
terminals of
thermal protector
for magnetron
or thermal
protector for
cavity by using
jumper lead.
No
Operation
Normal
Operation
PROBLEM
3-b
Check operation
of blower motor
when ST
AR
T
key
is touched.
Check resistance of
each winding after
removing lead wires.
(See page 6)
Normal HV
T
ransformer
Check H.V capacitor , H.V
.
diode or H.V fuse with an
ohm-meter after removing
the lead wires.( See page 7 )
∞
0
∞
0
Resistance
Correct
Normal H.V capacitor
,
H.V diode or H.V
. fuse.
Replace HV
T
ransformer
Normal
Magnetron
Normal H.V
capacitor ,
diode or fuse.
U
p
U
p
U
p
U
p
U
p
U
p
6
5
-11-
