STEP
SEQUENCE
RESUL
T
b
Resistance
OK
Replace control
circuit board.
(4) PROBLEM
Lo
w micro
w
a
v
e
po
w
e
r
output.
a
Nor
mal control
circuit board
Replace Blo
w
e
r
motor
∞
0
Resistance
incorrect
∞
274
Nor
mal
Resistance
Replace ther
mal protector
for magnetron or ther
mal
protector f
or ca
vity
.
∞
0
∞
0
Def
ectiv
e 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
∞
0
∞
0
Resistance
Incorrect
-12-
Nor
mal Blo
w
e
r
Motor
Measure resistance
of b
lo
w
er motor
(Appro
x 300 ohms)
No
Oper
ation
Nor
mal ther
mal protector f
o
r
magnetron or ther
mal
protector f
or ca
vity
.
Nor
mal
Oper
ation
T
empor
ar
ily
shor
t across
ter
minals of
ther
mal protector
for magnetron
or ther
mal
protector f
o
r
ca
vity b
y
using
jumper lead.
No
Oper
ation
Nor
mal
Oper
ation
PROBLEM
3-b
Chec
k oper
ation
of b
lo
w
er motor
when ST
AR
T
k
e
y
is touched.
Chec
k resistance of
each winding after
remo
ving lead wires
.
(See page 6 )
Nor
mal HV
T
ransf
or
mer
Chec
k H.V capacitor , H.V
.
diode or H.V fuse with an
ohm-meter after remo
ving
the lead wires
.( See page 6 )
Nor
mal H.V capacitor
,
H.V diode or H.V
. fuse
.
Replace HV
T
ransf
or
mer
Nor
mal
Magnetron
Nor
mal H.V
capacitor ,
diode or fuse
.