Read Sharp R-21FBSTM Service Manual online
R-21FBSTM/R-22FBSTM - 8
TROUBLESHOOTING CHART
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.
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 fuse F1. Check the monitored latch
switch and monitor switch before replacing
the F8A fuse.
a blown fuse F1. Check the monitored latch
switch and monitor switch before replacing
the F8A fuse.
CONDITION
PROBLEM
A
B
C
E
D E
E F
F
J
I
L
J
K
Home fuse blows when power cord is
plugged into wall outlet.
plugged into wall outlet.
"88:88"does not operate in display
when power cord is plugged into wall
outlet.
when power cord is plugged into wall
outlet.
Display does not operate properly
when STOP button is touched.
when STOP button is touched.
Oven lamp does not light, when door
is opened. (Display operates).
is opened. (Display operates).
Oven does not start when START
button is touched.(Display operates).
Fan motor does not operate (Oven
lamp lights).
lamp lights).
Turntable motor assembly does not
operate (Oven lamp lights).
operate (Oven lamp lights).
Oven or electrical parts does not stop
when timer knob is at "0" or STOP
button is touched.
when timer knob is at "0" or STOP
button is touched.
Display operates properly but all
electrical parts do not operate.
electrical parts do not operate.
Oven goes into cook cycle but shuts
down before end of cooking cycle.
down before end of cooking cycle.
Oven seems to be operating but little
or no heat is produced in oven load
(Microwave power control is set at
HIGH).
or no heat is produced in oven load
(Microwave power control is set at
HIGH).
Oven does not seem to be operating
properly during variable cooking
condition(Oven operates properly at
HIGH).
properly during variable cooking
condition(Oven operates properly at
HIGH).
Fuse F8A blows (F1)
OFF
CONDITION
COOKING
CONDITION
TEST PROCEDURE
POSSIBLE CAUSE
AND
DEFECTIVE PARTS
MAGNETRON
HIGH VOLTAGE TRANSFORMER
H.V. RECTIFIER ASSY
H.V.HARNESS
HIGH VOLTAGE CAPACITOR
MONITORED LATCH SWITCH
STOP SWITCH
MONITOR SWITCH
MAG THERMAL CUT--OUT 125
0
C
THERMAL CUT-OUT 125
0
C (OVEN)
FUSE F1
NOISE FILTER
TURNTABLE MOTOR
FAN MOTOR
TC TRANSFORMER
CONTROL UNIT
SWITCH UNIT
RELAY RY1,3,4
FOIL PATTERN ON P.W.B.
POWER SUPPLY CORD
SHORTED WIRE HARNESS
OPENED WIRE HARNESS
OVEN LAMP
BLOCKED VENTILATION OPENINGS
WRONG OPERATION
MIS-ADJUSTMENT OF SWITCHES
HOME FUSE OR BREAKER
NO POWER AT WALL OUTLET
BLOCKED COOLING FAN
I
G H
M
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