Sharp R-242M Service Manual ▷ View online
R-242M - 13
COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE
REMOVAL
1. CARRY OUT 3D CHECKS.
2. Disconnect the wire leads from the switches and control
2. Disconnect the wire leads from the switches and control
panel.
3. Remove the control panel assembly from the oven cavity
front flange. Referring to chapter "CONTROL PANEL
ASSEMBLY REMOVAL".
ASSEMBLY REMOVAL".
4. Remove the two (2) screw holding the latch hook to the
oven flange.
5. Remove the latch hook assembly from the oven flange.
6. To remove the switch.
6-1. With pushing outward on the tab that is holding the
6. To remove the switch.
6-1. With pushing outward on the tab that is holding the
switch, turn the switch so that the post is an axis.
6-2. Pull out the switch from the latch hook. Do not break the
post or tab of the latch hook.
6-3. Now the switch is free.
Re-install
1. Re-install each switch in its place. The monitored latch
switch is in the lower position and the monitor switch is
in the middle position. The stop switch is in the upper
position.
in the middle position. The stop switch is in the upper
position.
2. Re-connect wire leads to each switch. Refer to “Pictorial
Diagram”page 17.
3. Secure latch hook (with two (2) mounting screws) to
oven flange.
4. Re-install the control panel assembly to the oven cavity
4. Re-install the control panel assembly to the oven cavity
front flange.
5. Re-connect wire leads to the control unit. Refer to
“Pictorial Diagram”page 17.
6. Make sure that monitor switch is operating properly and
check continuity of the monitor circuit. Refer to chapter
MONITORED LATCH SWITCH, MONITOR SWITCH AND STOP SWITCH ADJUSTMENT
1. CARRY OUT 3D CHECKS.
If the monitored latch switch, stop switch and monitor switch
do not operate properly due to a misadjustment, the follow-
ing adjustment should be made.
2. Loosen the two (2) screws holding the latch hook to the
If the monitored latch switch, stop switch and monitor switch
do not operate properly due to a misadjustment, the follow-
ing adjustment should be made.
2. Loosen the two (2) screws holding the latch hook to the
flange of the oven front face.
3. With the 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 horizontal position of
the latch hook should be adjusted so that the monitor
switch is activated with the door closed. The vertical
position of the latch hook should be adjusted so that the
stop switch and the monitored latch switch are activated
with the door closed.
allowed by the upper and lower position of the latch hook
should be less than 0.5mm. The horizontal position of
the latch hook should be adjusted so that the monitor
switch is activated with the door closed. The vertical
position of the latch hook should be adjusted so that the
stop switch and the monitored latch switch are activated
with the door closed.
4. Secure the screws 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, make sure of the following.
1. In and out play of the 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 door
toward the oven face. Both results (play in the door)
should be less than 0.5mm.
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 door
toward the oven face. Both results (play in the door)
should be less than 0.5mm.
2. The monitored latch switch and stop switch interrupt the
circuit before the door can be opened.
3. The monitor switch contacts (COM-NC) close when the
door is opened.
4. Re-install outer case and check for microwave leakage
around the door with an approved microwave survey
meter. (Refer to Microwave Measurement Procedure.)
meter. (Refer to Microwave Measurement Procedure.)
Figure C-3. Latch Switch Adjustments
Latch hook
Tab
SW3: Stop switch
SW2: Monitor switch
SW1: Monitored latch switch
Tab
Tab
Latch hook
SW3: Stop switch
Door
SW2: Monitor switch
SW1: Monitored latch switch
Latch heads
“Test Procedure”, and Adjustment Procedure below.
Figure C-2. Latch Switch Removal
14
R-242M -
REMOVAL
1. Disconnect the power supply cord.
2. Open the door slightly.
3. Remove the choke cover taking care not to break clips
2. Open the door slightly.
3. Remove the choke cover taking care not to break clips
by inserting an iron plate (thickness of about 0.5mm) or
flat type screw driver to the gap between the choke
cover and door panel as shown Figure C-4 to free the
engaged parts.
flat type screw driver to the gap between the choke
cover and door panel as shown Figure C-4 to free the
engaged parts.
4. Release choke cover from door panel.
5. Now choke cover is free.
5. Now choke cover is free.
Figure C-4. Door Disassembly
6. Release two (2) pins of door panel from two (2) holes of
upper and lower oven hinges by lifting up.
7.
1. Remove door assy by removing screws (4).
8. Release door panel from tabs of door frame and remove
door frame by sliding the door panel downward.
9. Now, door panel with inner sealer film is free.
10. Tear inner sealer film from door panel.
11. Now, door panel is free.
12. Slide latch head upward and remove it from door frame
10. Tear inner sealer film from door panel.
11. Now, door panel is free.
12. Slide latch head upward and remove it from door frame
with releasing latch spring from door frame and latch
head.
head.
13. Now, latch head and latch spring are free.
14.
14.
Remove Glass Stopper Screw (noting position of
stopper) and slide stopper down while lifting up.
stopper) and slide stopper down while lifting up.
15.
Slide glass towards Glass Stopper position and
then down towards the lower edge of the door
frame.
frame.
16.
Lift upper edge of glass, which will now be free from
upper clips and remove from lower clips.
17.
Refitting is a reversal of the above when refitting,
ensure the glass and the glass stopper is in the
original position.
original position.
RE-INSTALL
1. Re-install the outer door glass to the door frame with the
glass stopper.
2. Hold the glass stopper with the one (1) screw.
3. Re-install latch spring to the head. Re-install latch spring
3. Re-install latch spring to the head. Re-install latch spring
to the door frame. Re-install latch head to the door
frame.
frame.
4. Re-install door panel to door frame by fitting tabs of door
frame to holes of door panel.
5. Put sealer film on door panel. Refer to “Inner Sealer
Film” and figure C-6, on how to handle the new film.
6. Catch two (2) pins of door panel on two (2) hole of upper
and lower oven hinges.
7. Re-install choke cover to door panel by pushing.
Note: After any service to the door;
(A) Make sure that monitored latch switch, stop switch
(A) Make sure that monitored latch switch, stop switch
and monitor switch are operating properly. (Refer
to chapter “Test Procedures”.).
to chapter “Test Procedures”.).
(B) An approved microwave survey meter should be
used to assure compliance with proper microwave
radiation emission limitation standards.
radiation emission limitation standards.
After any service, make sure of the following :
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 Microwave
Measurement Procedure.)
Measurement Procedure.)
Note:
The door on a microwave oven is designed to act
as an electronic seal preventing the leakage of
microwave energy from oven cavity during cook
cycle. This function does not require that 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 of themselves, indicate a leakage of
microwave energy from oven cavity.
as an electronic seal preventing the leakage of
microwave energy from oven cavity during cook
cycle. This function does not require that 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 of themselves, indicate a leakage of
microwave energy from oven cavity.
Figure C-5. Door Replacement
INNER SEALER FILM
Installation
1. Tear away the backing film.
3. Put the pasted side of the inner sealer film on the door
3. Put the pasted side of the inner sealer film on the door
panel.
10
5
4
12
8
7
9
11
3
2
1
Choke Cover
Door Frame
Putty Knife
6
Pin
Pin
Lower
Oven
Hinge
Oven
Hinge
Lower Oven
Hinge
Hinge
Upper
Oven
Hinge
Oven
Hinge
Upper Oven
Hinge
Hinge
Door Panel
Choke Cover
Door film
Finger tab
Backing film
Figure C-6. Inner Sealer Film
COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE
R-242M - 15
MICROWAVE MEASUREMENT
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
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 non-conductive material, such as glass or plastic, with an inside
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
±
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 standard whose accuracy can be
traced to National Physical Laboratory Standards.
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.
instructions, and any spacers are fitted to ensure that measurement is taken 5cm from the surface of the oven.
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.
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.
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
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
Dotted line indicates the path by the leakage detector.
Whilst the maximum leakage permitted in BS60335 2-25 is 50 /W/m
2
(equivalent to 5 W/cm
2
),it is not normal to detect any
significant leakage, and therefore any detected leakage should be investigated.
16
R-242M -
Figure 0-1 Schematic-OFF Condition, Door Closed
WIRING DIAGRAM
T: HIGH VOLTAGE
TRANSFORMER
WITH 150˚C THERMOSTAT
IN PRIMARY WINDING
WITH 150˚C THERMOSTAT
IN PRIMARY WINDING
MG: MAGNETRON
H.V. RECTIFIER
C:
H.V. CAPACITOR
0.88
H.V. CAPACITOR
0.88
µ
F/ AC2100V
TURNTABLE MOTOR
FAN MOTOR
OVEN LIGHT
D72
D3
D1
D71
D70
SW3: STOP
SWITCH
CONTROL UNIT
TC: OVEN THERMAL
CUT-OUT 125˚C
SW1: MONITORED
LATCH SWITCH
SW2: MONITOR
SWITCH
B2
B1
A5
A1
A3
OL
FM
TTM
N.O.
N.O.
N.C.
RY-1
COM.
N.O.
COM.
RY-2
EARTH
BLU
BRN
LIVE
NEUTRAL
G-Y
F1: FUSE
( F8A)
( F8A)
N
L
0.22
µ
/AC250V
680K/ 0.5W
10M/ 0.5W
NOISE SUPPRESSION COIL
0.0033µ/ 250V
0.0033µ/ 250V
NOISE FILTER
230V-240v
˜
50Hz
T: HIGH VOLTAGE
TRANSFORMER
WITH 150˚C THERMOSTAT
IN PRIMARY WINDING
WITH 150˚C THERMOSTAT
IN PRIMARY WINDING
MG: MAGNETRON
H.V. RECTIFIER
C:
H.V. CAPACITOR
0.88
H.V. CAPACITOR
0.88
µ
F/ AC2100V
TURNTABLE MOTOR
FAN MOTOR
OVEN LIGHT
D72
D3
D1
D71
D70
SW3: STOP
SWITCH
CONTROL UNIT
TC: OVEN THERMAL
CUT-OUT 125˚C
SW1: MONITORED
LATCH SWITCH
SW2: MONITOR
SWITCH
B2
B1
A5
A1
A3
OL
FM
TTM
N.O.
N.O.
N.C.
RY-1
COM.
N.O.
COM.
RY-2
EARTH
BLU
BRN
LIVE
NEUTRAL
G-Y
F1: FUSE
(F8A)
(F8A)
N
L
0.22
µ
/AC250V
680K/ 0.5W
10M/ 0.5W
NOISE SUPPRESSION COIL
0.0033µ/ 250V
0.0033µ/ 250V
NOISE FILTER
230V-240v
˜
50Hz
Figure 0-2 Schematic-ON Condition, Door Closed.
*
NOTE: PARTS WITH POTENTIALS ABOVE 250V
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