Sharp R-21AT Service Manual ▷ View online
R-21AT
23
1. CARRY OUT 3D CHECKS.
2. Remove the control panel assembly referring to "CON-
2. Remove the control panel assembly referring to "CON-
TROL PANEL ASSEMBLY REMOVAL".
3. Disconnect the leads from all switches.
4. Remove the two (2) screws holding the latch hook to
4. Remove the two (2) screws holding the latch hook to
the oven cavity.
5. Remove the latch hook.
6. Push the retaining tab outward slightly and remove the
6. Push the retaining tab outward slightly and remove the
switch.
Re-install
1. Re-install each switch in its place. The 2nd. interlock
1. Re-install each switch in its place. The 2nd. interlock
relay control switch and the latch switch are in the lower
position and the 1st. interlock switch is in the upper
position. The monitor switch is in the middle position.
position and the 1st. interlock switch is in the upper
position. The monitor switch is in the middle position.
2. Re-connect wire leads to each switch.
Refer to pictorial diagram.
3. Secure latch hook (with two (2) mounting screws) to
oven flange.
1ST. INTERLOCK SWITCH, LATCH SWITCH, 2ND. INTERLOCK RELAY CONTROL SWITCH,
AND MONITOR SWITCH REMOVAL
If the 1st. interlock switch, latch switch, 2nd. interlock relay
control switch and monitor switch do not operate properly
due to a mis-adjustment, the following adjustment should
be made.
1. CARRY OUT 3D CHECKS.
2. Loosen the two (2) screws holding the latch hook to the
control switch and monitor switch do not operate properly
due to a mis-adjustment, the following adjustment should
be made.
1. CARRY OUT 3D CHECKS.
2. Loosen the two (2) screws holding the latch hook to the
oven cavity front flange.
3. With door closed, adjust latch hook by moving it back
and forth, and up and down. In and out play of the door
allowed by the upper and lower position of the latch
hook should be less than 0.5mm. The vertical position
of the latch hook should be adjusted so that the 1st.
interlock switch, latch switch and 2nd. interlock relay
control switch are activated with the door closed. The
horizontal position of the latch hook should be adjusted
so that the plunger of the monitor switch is pressed with
the door closed.
allowed by the upper and lower position of the latch
hook should be less than 0.5mm. The vertical position
of the latch hook should be adjusted so that the 1st.
interlock switch, latch switch and 2nd. interlock relay
control switch are activated with the door closed. The
horizontal position of the latch hook should be adjusted
so that the plunger of the monitor switch is pressed with
the door closed.
4. Secure the screws with washers firmly.
5. Check the operation of all switches. If each switch has
5. Check the operation of all switches. If each switch has
not activated with the door closed, loosen screw and
adjust the latch hook position.
adjust the latch hook position.
After adjustment, check the following.
1. In and out play of door remains less than 0.5mm when
1. In and out play of door remains less than 0.5mm when
in the latched position. First check upper position of
latch hook, pushing and pulling upper portion of door
toward the oven face. Then check lower portion of the
latch hook, pushing and pulling lower portion of the
latch hook, pushing and pulling upper portion of door
toward the oven face. Then check lower portion of the
latch hook, pushing and pulling lower portion of the
4. Make sure that the monitor switch is operating properly
and check continuity of the monitor circuit. Refer to
chapter "Test Procedure" and Adjustment procedure.
chapter "Test Procedure" and Adjustment procedure.
Figure C-4. Switches
1ST. INTERLOCK SWITCH, LATCH SWITCH, 2ND. INTERLOCK RELAY CONTROL SWITCH,
AND MONITOR SWITCH ADJUSTMENT
door toward the oven face. Both results (play in the
door) should be less than 0.5mm.
door) should be less than 0.5mm.
2. The 1st. interlock switch, latch switch and 2nd. inter-
lock relay control switch interrupt the circuit before the
door can be opened.
door can be opened.
3. Monitor switch contacts close when door is opened.
4. Re-install outer case and check for microwave leakage
4. Re-install outer case and check for microwave leakage
around door with an approved microwave survey meter.
(Refer to Microwave Measurement Procedure.)
(Refer to Microwave Measurement Procedure.)
Figure C-5. Latch Switch Adjustments
Latch Hook
Tabs
Tab
Tab
Tab
Tab
Monitor Switch
Latch Switch
(Cabinet side)
(Cabinet side)
1st. Interlock Switch
2nd. Interlock Relay
Control Switch (Oven side)
Control Switch (Oven side)
Latch Hook
Latch Switch
Lever A
Latch Switch
Lever B
Latch Switch
Lever C
Latch Head
Latch Head
Handle
Lever
Door
Handle
Latch
Lever
Monitor
Switch
Switch
1st. Interlock Switch
2nd. Interlock Relay
Control Switch
Control Switch
Latch Switch
CHOKE COVER
1. Disconnect the oven from the power supply.
2. Open the oven door and wedge it open.
3. Insert a putty knife (thickness of about 0.5mm) into the
1. Disconnect the oven from the power supply.
2. Open the oven door and wedge it open.
3. Insert a putty knife (thickness of about 0.5mm) into the
DOOR PARTS REPLACEMENT
gap between the choke cover and door frame as shown
in Figure C-6 to free engaging parts.
in Figure C-6 to free engaging parts.
4. Pry the choke cover by inserting a putty knife as shown
in Figure C-6.
24
R-21AT
Upper Oven
Hinge
Hinge
Upper
Oven
Hinge
Oven
Hinge
Lower
Oven
Hinge
Oven
Hinge
Lower
Oven
Hinge
Oven
Hinge
Pin
Pin
Choke Cover
Door
Panel
Panel
5. Release choke cover from door panel.
6. Now choke cover is free.
6. Now choke cover is free.
Figure C-6. Door Disassembly
7. Release two (2) pins of door panel from two (2) holes
of upper and lower oven hinges by lifting up.
8. Now, door sub assembly is free from oven cavity.
DOOR PANEL REMOVAL
9. Remove the four (4) screws holding the door panel to
9. Remove the four (4) screws holding the door panel to
the door frame.
10.Release door panel from seven (7) tabs of door frame
by sliding door panel downward.
11.Now, the door panel is free.
DOOR HANDLE REMOVAL
12.Release the latch spring from the tab of the latch angle
12.Release the latch spring from the tab of the latch angle
assembly.
13.Remove the two (2) screws holding the door handle
and the latch angle assembly through the door frame.
14.Now, door handle is free.
LATCH HEADS REMOVAL
15.Remove the one (1) screw holding the latch angle
15.Remove the one (1) screw holding the latch angle
assembly to the door frame.
16.Remove the latch angle assembly together with the
latch lever, latch spring and the upper and lower latch
heads from the door frame.
heads from the door frame.
17.Release the latch lever together with the latch spring
and the latch heads from the latch angle assembly.
18.Release the two (2) latch heads from the latch lever.
19.Now, the upper and lower latch heads are free.
19.Now, the upper and lower latch heads are free.
FRONT DOOR GLASS REMOVAL
(After DOOR PANEL REMOVAL)
12.Remove the four (4) screws holding the glass stopper
(After DOOR PANEL REMOVAL)
12.Remove the four (4) screws holding the glass stopper
U to the door frame and remove the glass stopper U.
13.Remove the two (2) screws holding the glass stopper
R to the door frame and remove the glass stopper R.
14.Slide the front door glass left at first and then slide
upwards to release it from the tabs holding it.
17.Now, the front door glass is free
DOOR CASE REMOVAL
(After DOOR PANEL REMOVAL)
12.Straighten all tabs of the door case holding the door
(After DOOR PANEL REMOVAL)
12.Straighten all tabs of the door case holding the door
case to the door frame.
13.Release door case from the door frame.
17.Now, the door case is free
17.Now, the door case is free
NOTE: At this moment, the door badge is attached on the
door case.
RE-INSTALL OF THE DOOR
1. Re-install all door parts except the choke cover.
2. Catch two (2) pins of door panel on two (2) holes of
1. Re-install all door parts except the choke cover.
2. Catch two (2) pins of door panel on two (2) holes of
upper and lower oven hinges.
3. Re-install choke cover to door panel by pushing.
NOTE: After any service to the door;
(A) Make sure that door sensing switch and second-
ary interlock switch are operating properly. (Re-
fer to chapter "Test Procedures".).
fer to chapter "Test Procedures".).
(B) An approved microwave survey meter should be
used to assure compliance with proper micro-
wave radiation emission limitation standards.
(Refer to Microwave Measurement Procedure.)
wave radiation emission limitation standards.
(Refer to Microwave Measurement Procedure.)
After any service, make sure of the following :
1. Door latch heads smoothly catch latch hook through
1. Door latch heads smoothly catch latch hook through
latch holes and that latch head goes through center of
latch hole.
latch hole.
2. Deviation of door alignment from horizontal line of
cavity face plate is to be less than 1.0mm.
3. Door is positioned with its face pressed toward cavity
face plate.
4. Check for microwave leakage around door with an
approved microwave survey meter. (Refer to Micro-
wave Measurement Procedure.)
wave Measurement Procedure.)
Note: The door on a microwave oven is designed to act as
an electronic seal preventing the leakage of micro-
wave energy from oven cavity during cook cycle.
This function does not require that the door be air-
tight, moisture (condensation)-tight or light-tight.
Therefore, occasional appearance of moisture, light
or sensing of gentle warm air movement around
oven door is not abnormal and do not in themselves
indicate a leakage of microwave energy from oven
cavity.
wave energy from oven cavity during cook cycle.
This function does not require that the door be air-
tight, moisture (condensation)-tight or light-tight.
Therefore, occasional appearance of moisture, light
or sensing of gentle warm air movement around
oven door is not abnormal and do not in themselves
indicate a leakage of microwave energy from oven
cavity.
Putty Knife
Door Frame
Choke Cover
Figure C-7. Door Replacement
R-21AT
25
1. Disconnect the oven from the power supply.
2. Open the oven door and wedge it open.
3. Make sure that the smooth surface of the ceramic shelf
2. Open the oven door and wedge it open.
3. Make sure that the smooth surface of the ceramic shelf
face up.
4. Make sure that the rubber packing without a fin of the
ceramic shelf faces the front of the oven.
NOTE: The three (3) rubber packings with the fins and the
one (1) rubber packing without a fin are attached
to the four (4) edges of the ceramic shelf. The one
(1) rubber packing without a fin is the front edge of
the ceramic shelf.
to the four (4) edges of the ceramic shelf. The one
(1) rubber packing without a fin is the front edge of
the ceramic shelf.
5. Put the front edge of the ceramic shelf into the front
edge of the oven cavity bottom plate.
6. Push down the rear edge of the ceramic shelf into the
oven cavity bottom plate.
7. Now, the ceramic shelf is installed.
INSTALLATION OF CERAMIC SHELF
Rear Edge
Push
Front Edge
Ceramic
Shelf
Shelf
Oven Cavity
WARNING
Make sure that the rubber packing is not caught be-
tween the oven door and the oven cavity front plate, to
avoid possible exposure to excessive microwave en-
ergy.
tween the oven door and the oven cavity front plate, to
avoid possible exposure to excessive microwave en-
ergy.
MICROWAVE MEASUREMENT
PROCEDURE
1. Place the beaker containing the water load in the oven
cavity at the centre of the turntable. The placing of this
standard load in the oven is important, not only to
protect the oven, but also to ensure that any leakage it
is not disguised by too large a load absorbing energy.
standard load in the oven is important, not only to
protect the oven, but also to ensure that any leakage it
is not disguised by too large a load absorbing energy.
2. Close the oven door, and with the power level set to
FULL, turn the oven ON with the timer set for a few
minutes operation. Should the water begin to boil
before the test has been completed, it should be
replaced.
minutes operation. Should the water begin to boil
before the test has been completed, it should be
replaced.
3. As shown in the diagram below, move the probe slowly
(not faster than 2.5 cm/sec.);-
a) around the edge of the door following the gap
b) across the face of the door
c) across any vents in the oven’s sides, rear or top
b) across the face of the door
c) across any vents in the oven’s sides, rear or top
Dotted line indicates the path taken by the leakage detector.
Whilst the maximum leakage permitted in BS EN 60335-2-25 is 50 W/m
2
(equivalent to 5 mW/cm
2
), it is not normal to detect
any significant leakage, and therefore any detected leakage should be investigated.
After any repair, the microwave oven must be checked for
microwave leakage to ensure continued safe operation.
BS EN 60335-2-25 specifies that the maximum permitted
leakage with a load of 275 ml is 50 W/m
microwave leakage to ensure continued safe operation.
BS EN 60335-2-25 specifies that the maximum permitted
leakage with a load of 275 ml is 50 W/m
2
(equivalent to 5
mW/cm
2)
at a distance of 5 cm from the oven.
PREPARATION
The following items are required to carry out this test:-
1. A low form of 600 ml beaker made from an electrically
1. A low form of 600 ml beaker made from an electrically
non-conductive material, such as glass or plastic, with
an inside diameter of approximately 8.5 cm. This must
contain 275
an inside diameter of approximately 8.5 cm. This must
contain 275
±
15 ml of water, at an initial temperature
of 20
±
2˚C.
2. A leakage detector which has been calibrated within
the preceding 12 months to a stand whose accuracy
can be traced to National Physical Laboratory Stand-
ards.
can be traced to National Physical Laboratory Stand-
ards.
Recommended instruments are:
Apollo “XI”
Celtec “A100”
Celtec “A100”
Before commencing the test, check that the leakage
detector is functioning and adjusted according to the
manufacturer’s instructions, and any spacers are fitted to
ensure that measurement is taken 5cm from the surface of
the oven.
detector is functioning and adjusted according to the
manufacturer’s instructions, and any spacers are fitted to
ensure that measurement is taken 5cm from the surface of
the oven.
26
R-21AT
SCHEMATIC
NOTE: CONDITION OF OVEN
1. DOOR CLOSED.
2. "SELECT TIME" PAD TOUCHED.
3. COOKING TIME ENTERED.
4. START PAD TOUCHED.
2. "SELECT TIME" PAD TOUCHED.
3. COOKING TIME ENTERED.
4. START PAD TOUCHED.
Figure O-2 Oven Schematic-Cooking Condition
SCHEMATIC
NOTE: CONDITION OF OVEN
1. DOOR CLOSED.
2. : APPEAR ON DISPLAY.
1. DOOR CLOSED.
2. : APPEAR ON DISPLAY.
NOTE:
Indicates components with potential above 250 V.
Figure O-1 Oven Schematic-OFF Condition
HIGH VOLTAGE
TRANSFORMER
MAGNETRON
H.V. RECTIFIER
CAPACITOR
1.07
µ
F
AC2400V
ANTENNA MOTOR
FAN MOTOR
OVEN LAMP
MONITOR SWITCH
CONTROL
UNIT
THERMAL
CUT-OUT
125˚C (OVEN)
CUT-OUT
125˚C (OVEN)
LATCH
SWITCH
SWITCH
B1
B2
A5
A7
OL
FM
AM
THERMAL
CUT-OUT
145˚C (MG)
CUT-OUT
145˚C (MG)
RY-3
RY-2
1ST. INTERLOCK
SWITCH
SWITCH
2ND. INTERLOCK RLAY
CONTROL SWITCH
CONTROL SWITCH
MONITOR
RESISTOR
0.8/20W
EARTH
230 - 240V
˜
50Hz
BLU
BRN
LIVE
NEUTRAL
G-Y
FUSE
M10A
N
L
DISCHARGE RESISTOR 680 k
Ω
NOISE SUPPRESSION COIL
NOISE FILTER
H.V. FUSE
0.75A
LINE BYPASS
CAPACITOR
0.0033
µ
F/ AC 250V
DISCHARGE
RESISTOR 10M
Ω
LINE BYPASS
CAPACITOR
0.0033
µ
F/ AC 250V
LINE CROSS CAPACITOR 0.068
µ
F/ AC 250V
HIGH VOLTAGE
TRANSFORMER
MAGNETRON
H.V. RECTIFIER
CAPACITOR
1.07
µ
F
AC2400V
ANTENNA MOTOR
FAN MOTOR
OVEN LAMP
MONITOR SWITCH
CONTROL
UNIT
THERMAL
CUT-OUT
125˚C (OVEN)
CUT-OUT
125˚C (OVEN)
LATCH
SWITCH
SWITCH
B1
B2
A5
A7
OL
FM
AM
THERMAL
CUT-OUT
145˚C (MG)
CUT-OUT
145˚C (MG)
RY-3
RY-2
1ST. INTERLOCK
SWITCH
SWITCH
2ND. INTERLOCK RLAY
CONTROL SWITCH
CONTROL SWITCH
MONITOR
RESISTOR
0.8/20W
EARTH
230 - 240V
˜
50Hz
BLU
BRN
LIVE
NEUTRAL
G-Y
FUSE
M10A
N
L
DISCHARGE RESISTOR 680 k
Ω
NOISE SUPPRESSION COIL
NOISE FILTER
H.V. FUSE
0.75A
LINE BYPASS
CAPACITOR
0.0033
µ
F/ AC 250V
DISCHARGE
RESISTOR 10M
Ω
LINE BYPASS
CAPACITOR
0.0033
µ
F/ AC 250V
LINE CROSS CAPACITOR 0.068
µ
F/ AC 250V
Click on the first or last page to see other R-21AT service manuals if exist.