Read Sharp R-556D (serv.man2) Service Manual online
R556D
7 – 1
R556D
Service Manual
CHAPTER 7.
TROUBLESHOOTING GUIDE
[1] FOREWORD
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 Pro-
cedure”section.
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 Pro-
cedure”section.
IMPORTANT:
If the oven becomes inoperative because of a blown fuse F10A in the
1st. latch switch - 2nd. interlock relay - monitor switch circuit, check the
1st. latch switch, 2nd. interlock relay and monitor switch before replac-
ing the fuse F10A.
1st. latch switch - 2nd. interlock relay - monitor switch circuit, check the
1st. latch switch, 2nd. interlock relay and monitor switch before replac-
ing the fuse F10A.
[2] CHART
CONDITION
TEST PROCEDURE
A B C D E E E F G G H K L M N
RE
CK
CK
RE
CK
CK
CK
CK
CK
I
J
POSSIBLE CAUSE
AND
DEFECTIVE PARTS
MAGNETRON
HIGH VOL
TA
G
E TRANSFORMER
H.V
. RECTIFIER ASSEMBL
Y
HIGH VOL
TAGE CAP
A
CIT
O
R
1ST
. LA
TCH
SWIT
CH
2ND.
INTERLOCK R
E
LA
Y C
O
N
T
ROL SWITCH
MONIT
O
R SWITCH
TEMPERA
T
URE FUSE
(OV
E
N, MG
)
FA
N
M
O
T
O
R
TU
RNT
ABLE MOT
O
R
FU
S
E
F
10A
T
O
UCH C
O
NT
ROL P
A
NEL
KEY UNIT
RELA
Y (R
Y
-1, R
Y
-2)
FOIL P
A
T
ERN ON P
.W
.B.
POW
E
R SUP
P
LY
CO
RD
SHOR
TED WIRE HARN
ESS
OPEN
ED
WIRE HARNESS
OVE
N
LAMP
W
A
LL OUTLET
MISADJUSTMENT SW
ITCH
HOME FUSE OR BREAKER
BLOCKED COO
L
ING
F
A
N
BLOCKED VENTILA
TION
NOISE FIL
T
ER
HIGH VOL
TA
G
E FUSE
PROBLEM
OFF
CONDITION
Home fuse blows when power supply
cord is plugged in to wall outlet.
cord is plugged in to wall outlet.
{ {
{
FUSE 10A blows when power supply
cord is plugged into wall outlet.
cord is plugged into wall outlet.
{
{
{
Display does not show anything when
power supply cord is plugged into wall
outlet.
power supply cord is plugged into wall
outlet.
{
{ {
{ {
{
{
{
{
Display does not operate properly
when STOP/CLEAR key is touched.
when STOP/CLEAR key is touched.
{
{ {
{
{
Oven lamp does not light at door
opened. (Display appears.)
opened. (Display appears.)
{
{
{
{ { {
ON
CONDITION
Oven does not start when the START
button is pressed. (Display appears)
button is pressed. (Display appears)
{
{ { {
{
{
Oven lamp does not light (Display
appears.)
appears.)
{
{
{ {
Fan motor does not operate. (Display
appears.)
appears.)
{
{
{
{
{
{
Turntable motor assembly does not
operate. (Display appears.)
operate. (Display appears.)
{
{
{
{
{
Oven or any electrical parts does not
stop when cooking time is 0 or STOP/
CLEAR key is touched.
stop when cooking time is 0 or STOP/
CLEAR key is touched.
{
{
Oven seems to be operating but little or
no heat is produced in oven load.
(Microwave power level is set at 100%)
no heat is produced in oven load.
(Microwave power level is set at 100%)
{ { { {
{
{
{
{
Oven does not seems to be operating
properly when 70%, 50%, 30% or 10%
is set. (Oven operates properly at 100%
and then the STOP/CLEAR key is
touched the oven stops.)
properly when 70%, 50%, 30% or 10%
is set. (Oven operates properly at 100%
and then the STOP/CLEAR key is
touched the oven stops.)
{
{
Oven goes into cook cycle but shuts
down before end of cooking cycle.
down before end of cooking cycle.
{
{
{ {
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