Sharp R-1500AT, Service Manual

Page: 13 / 56

R1500AT
5 – 1
R1500AT
Service Manual
CHAPTER 5.
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.
IMPORTANT:
If the oven becomes inoperative because of a blown weak point F1 (or F2), check the monitor switches SW3 (or SW4), primary interlock relay RY1,
door sensing switch SW5 and secondary interlock switch SW1 (or SW2), before replacing the weak point F1 (or F2).
Never touch any part in the circuit with your hand or an uninsulated tool while the power supply is connected.
Home
fuse
blows
when
power
cord
is
plugged
into
wall
receptacle
"
.
"
does
not
appear
in
display
when
power
cord
is
first
plugged
into
wall
receptacle.
Oven
lamp
does
not
g
o
o
n
for
1
m
inute
a
fter
door
is
opened.
Oven
lamp
and
antenna
motors
d
o
not
go
on
in
cook
cycle.
Fan
motor
does
not
operate.
Exhaust
fan
does
not
operate.
Exhaust
motor
does
not
operate.
OFF CONDITION CONDITION
PROBLEM
COOKING CONDITION
POSSIBLE
CAUSE
A
ND
DEFECTIVE
PARTS
TEST
P
ROCEDURE
MAGNETRONMG1, MG2
POWERTRANSFORMER T1,T2
H.V.RECTIFIER ASSEMBLY(1), (2)
HIGHV OLTAGECAPACITORC1, C2
SECONDARYINTERLOCK SWITCH SW1,SW2
PRIMARYINTERLOCK SYSTEM
DOORSENSING SWITCHSW5
MONITORSWITCH SW3,SW4
WEAKPOINT (inNoise filter)
MAGNETRONTEMP. FUSETF1, TF2
OVENTEMPERATURE FUSETF3
OVENLAMP ORSOCKET
FANMOTORS FM
EXHAUSTFAN EF
EXHAUSTMOTOR EM
FUSEF8 F1,F2
WEAKPOINTS (forFan motors)
WEAKPOINT (forExhaust fanm otor)
EXHAUSTTHERMISTOR
MAGNETRONTHERMISTOR TH
NOISEFILTER
KEYUNITS
POWERUNIT
RELAYUNIT
CONTROLUNIT
SWITCHUNIT.
AIRFLOW BLOCKED
LOOSEWIRING
SHORTIN POWERSUPPLY CORD
NOPOWER ATOUTLET
LOWPOWER SUPPLYVOLTAGE
AB
C
D
E
F
F
G
J
KK
H
I
I
M
L
O
Q
R
P
N
Weak
point
(in
noise
filter)
blows
when
pow-
er
cord
is
plugged
into
wall
receptacle.
Oven
doen
not
g
o
into
c
ook
c
ycle
w
hen
START
pad
on
the
door
is
touched.
Oven
does
not
g
o
into
c
ook
cycle
when
START
pad
is
touched.
Variable
cooking
does
not
o
perates
proper
-
ly
,
e
xc
e
p
t
H
IG
H
power
functions.
Low
or
no
power
is
produced
during
cook
-
ing
condition.
(The
food
is
heated
incom
-
pletely
or
not
heated
at
all.)
Oven
goes
into
a
cook
cycle
b
ut
shuts
d
own
before
and
off
cooking
cycle.
It
seems
that
the
output
power
is
low
-
er
or
higher
than
the
rated
one.