R-98STMA (serv.man11). Component Replacement And Adjustment Procedure - Sharp Home Appliance Service Manual (repair manual)

r-98stma (serv.man11) service manual
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R-98STMA (serv.man11)
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7
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259.68 KB
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PDF
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Service Manual
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Device
Home Appliance / Microwave Oven / Component Replacement And Adjustment Procedure
File
r-98stma-sm11.pdf
Date

Read Sharp R-98STMA (serv.man11) Service Manual online

R98STMAA
11 – 1
R98STMAA
Service Manual
 
CHAPTER 11. 
COMPONENT REPLACEMENT AND ADJUSTMENT PROCE-
DURE
[1] BEFORE OPERATING
Microwave ovens contain circuitry capable of producing very high voltage and current, contact with following parts may result in severe, possibly fatal,
electric shock.
(Example)
High Voltage Capacitor, High Voltage Transformer, Magnetron, High Voltage Rectifier Assembly, High Voltage fuse, High Voltage Harness etc..
WARNING:
Avoid possible exposure to microwave energy. Please follow the instructions below before operating
the oven.
1) Disconnect the power supply cord.
2) Visually check the door and cavity face plate for damage (dents,
cracks, signs of arcing etc.).
Carry out any remedial work that is necessary before operating the
oven.
Do not operate the oven if any of the following conditions exist;
1) Door does not close firmly.
2) Door hinge, support or latch hook is damaged.
3) The door gasket or seal is damaged.
4) The door is bent or warped.
5) There are defective parts in the door interlock system.
6) There are defective parts in the microwave generating and trans-
mission assembly.
7) There is visible damage to the oven.
Do not operate the oven:
1) Without the RF gasket (Magnetron).
2) If the wave guide or oven cavity are not intact.
3) If the door is not closed.
4) If the outer case (cabinet) is not fitted.
To prevent an electric shock, take the following manners.
1. Before wiring, 
1) Disconnect the power supply cord.
2) Open the door and block it open.
3) Discharge the high voltage capacitor and wait for 60 seconds.
2. Don't let the wire leads touch to the following parts;
1) High voltage parts:
Magnetron, High voltage transformer, High voltage capacitor
and High voltage rectifier assembly.
2) Hot parts:
Grill heating element, Convection heating element, Oven lamp,
Magnetron, High voltage transformer and Oven cavity.
3) Sharp edge:
Bottom plate, Oven cavity, Waveguide flange, Chassis support
and other metallic plate.
4) Movable parts (to prevent a fault)
Fan blade, Fan motor, Switch, Turntable motor, Convection
motor, convection fan and cooling fan.
3. Do not catch the wire leads in the outer case cabinet.
4. Insert the positive lock connector certainly until its pin is locked.
And make sure that the wire leads should not come off even if the
wire leads is pulled.
5. To prevent an error function, connect the wire leads correctly, refer-
ring to the Pictorial Diagram. 
Please refer to ‘OVEN PARTS, CABINET PARTS, CONTROL PANEL PARTS, DOOR PARTS’, when carrying out any of the following removal proce-
dures:
[2] OUTER CASE REMOVAL
To remove the outer case, procedure as follows.
1. Disconnect the oven from power supply.
2. Open the oven door and wedge it open.
3. Remove the one (1) screw holding the air duct to the oven cavity
rear plate. 
4. Remove the air duct.
5. Remove the nine (9) screws from rear and along the side edge of
case.
6. Slide the entire case back about 3 cm to free it from retaining clips
on the cavity face plate.
7. Lift the entire case from the oven.
8. Discharge the H.V. capacitor before carrying out any further work.
9. Do not operate the oven with the outer case removed.
NOTE: Step 1, 2 and 8 form the basis of the 3D checks.
CAUTION: DISCHARGE HIGH VOLTAGE CAPACITOR BEFORE
TOUCHING ANY OVEN COMPONENT OR WIRING.
[3] HIGH VOLTAGE COMPONENTS REMOVAL
(HIGH VOLTAGE CAPACITOR AND HIGH VOLTAGE RECTIFIER ASSEMBLY)
To remove the components, proceed as follows.
1. CARRY OUT 3D CHECKS.
2. Disconnect the filament lead of the high voltage transformer and
the high voltage wire of the high voltage transformer from the high
voltage capacitor.
3. Disconnect the high voltage wire from the magnetron.
 
WARNING AGAINST HIGH VOLTAGE:
WARNING FOR WIRING
R98STMAA
11 – 2
4. Remove one (1) screw holding earth side terminal of the high volt-
age rectifier assembly to the base plate through the capacitor
holder.
5. Release the capacitor holder from the base plate.
6. Remove the high voltage capacitor from the capacitor holder.
7. Disconnect the high voltage rectifier assembly from the high volt-
age capacitor.
8. Now, the high voltage rectifier assembly and the high voltage
capacitor should be free.
CAUTION: WHEN REPLACING HIGH VOLTAGE RECTIFIER
ASSEMBLY, ENSURE THAT THE CATHODE (EARTH)
CONNECTION IS SECURELY FIXED TO THE BASE
PLATE THROUGH THE CAPACITOR HOLDER WITH AN
EARTHING SCREW.
[4] HIGH VOLTAGE TRANSFORMER REMOVAL
To remove the components, proceed as follows.
1. CARRY OUT 3D CHECKS.
2. Disconnect the main wire harness from the high voltage trans-
former.
3. Disconnect the filament leads and high voltage wire of high voltage
transformer from high voltage capacitor and the magnetron.
4. Remove the two (2) screws holding the transformer to the base
plate.
5. Remove the transformer.
6. Now the high voltage transformer is free.
[5] MAGNETRON REMOVAL
1. CARRY OUT 3D CHECKS.
2. Disconnect the H.V. wire and filament lead of the transformer from
the magnetron.
3. Carefully remove two (2) screws holding the magnetron to the
waveguide, when removing the screws hold the magnetron to pre-
vent it from falling.
4. Remove the one (1) screw holding the magnetron to the chassis
support.
5. Remove the magnetron from the waveguide with care so the mag-
netron antenna is not hit by any metal object around the antenna.
6. Now, the magnetron is free.
CAUTION: CAUTION: WHEN REPLACING THE MAGNETRON, BE
SURE THE R.F. GASKET IS IN PLACE AND THE MAG-
NETRON MOUNTING SCREWS ARE TIGHTENED
SECURELY.
[6] CONTROL PANEL ASSEMBLY REMOVAL
1. CARRY OUT 3D CHECKS.
2. Disconnect the wire leads and the connectors from the control unit.
3. Remove the one (1) screw holding the control panel to the oven
cavity face plate.
4. Remove the one (1) screw holding the earth wire to the oven cavity
face plate.
5. Lift up the control panel assembly and pull it forward. 
Now the control panel assembly is free.
NOTE: 1) Before attaching a new key unit, wipe off remaining adhe-
sive on the control panel frame surfaces completely with a
soft cloth soaked in alcohol.
2) When attaching the key unit to the control panel frame,
adjust the upper edge and right edge of the key unit to the
correct position of control panel frame.
3) Stick the key unit firmly to the control panel frame by rub-
bing with soft cloth not to scratch.
[7] FAN MOTOR REREPLACEMENT
1. REMOVAL
1. CARRY OUT 3D CHECKS.
2. Remove the one (1) screw holding the noise filter to the chassis
support.
3. Release the noise filter from the tabs of the fan duct.
4. Remove the three(3) screw holding the chassis support to the oven
cavity front flange, back plate, and the magnetron.
5. Remove the chassis support from the oven cavity.
6. Disconnect the wire leads from the fan duct.
7. Remove the one (1) screw holding the fan duct to the back plate.
8. Release the tabs of the fan duct from back plate.
9. Remove the fan duct from the oven.
10.Remove the fan blade from the fan motor shaft according to the fol-
lowing procedure.
i)
Hold the edge of the rotor of the fan motor by using a pair of
groove joint pliers.
CAUTION: • Make sure that no swarf from the rotor enters the gap
between the rotor & stator of the fan motor.
• Avoid touch the coil of the fan motor with the pliers as
the coil may become cut or damaged.
• Avoid deforming the bracket whilst using the pliers.
ii) Remove the fan blade assembly from the shaft of the fan motor
by pulling and rotating the fan blade with your hand.
iii) Now, the fan blade is free.
CAUTION: Do not re-use the removed fan blade as the fixing hole may
be oversize.
11.Remove the two (2) screws holding the fan motor to the fan duct.
12.Now, the fan motor is free.
2. INSTALLATION
1. Install the fan motor to the fan duct with the two (2) screws and
nuts.
2. Install the fan blade to the fan motor shaft according to the following
procedure.
i)
Hold the centre of the bracket which supports the shaft of the
fan motor on a flat table.
ii) Apply the screw lock tight into the hole (for shaft) of the fan
blade.
iii) Install the fan blade to the shaft of fan motor by pushing the fan
blade with a small, light weight, ball peen hammer or rubber
mallet.
R98STMAA
11 – 3
CAUTION: • Do not hit the fan blade when installing because the
bracket may be deformed.
• Make sure that the fan blade rotates smoothly after
installation.
• Make sure that the axis of the shaft is not slanted.
3. Insert the tabs of the fan duct to the back plate.
4. Install the fan duct to the back plate with the one (1) screw.
5. Re-install the chassis support to the oven cavity with the four (4)
screws.
6. Install the noise filter to the fan duct and the chassis support with
the one (1) screw.
7. Re-connect the wire leads to the fan motor.
Figure C-1. Fan Motor Replacement
[8] TURNTABLE MOTOR REPLACEMENT
1. REMOVAL
1. Disconnect the oven from the power supply. 
2. Remove the turntable and roller stay from the oven cavity.
3. Turn the oven over.
4. Cut the three (3) bridges holding the turntable motor cover to the
base plate with cutting pliers as shown in Figure C-2(a).
CAUTION: DO NOT DROP THE TURNTABLE MOTOR COVER INTO
THE OVEN AFTER CUTTING THE BRIDGES. BECAUSE
IT WILL DAMAGE THE WIRE LEADS OF THE MOTOR
AND IT IS DIFFICULT TO REMOVE IT OUT OF THE
OVEN.
5. Remove the turntable motor cover from the base plate.
6. Disconnect the wire leads from the tu Figure C-2(b)rntable motor.
7. Remove the two (2) screws holding the turntable motor to the oven
cavity back plate.
8. Remove the turntable motor from the turntable motor angle. Now,
the turntable motor is free.
2. REINSTALL
1. Remove the any sharp edges on the turntable motor cover and the
base plate with the cutting pliers.
2. Re-install turntable motor by locating shaft onto coupling to the
oven cavity base plate with the two (2) screws.
3. Re-connect the wire leads to the turntable motor.
4. Insert the one (1) tab of the turntable motor cover into the slit of the
base plate as shown in Figure C-2(b).
5. Re-install the turntable motor cover to the base plate with the screw
(XHPS740P08K00) as shown in Figure C-2(b).
Figure C-2(a) Turntable Motor Cover Replacement 
Figure C-2(b) Turntable Motor Cover Reinstall
[9] CONVECTION MOTOR AND CONVECTION HEATING ELEMENT REMOVAL
1. CONVECTION UNIT ASSEMBLY REMOVAL
1. CARRY OUT 3D CHECKS.
Now, the outer case cabinet and the air duct should have been
removed.
2. Remove the one (1) screw holding the earth wire of the power sup-
ply cord to the back plate.
3. Release the power supply cord from the back plate.
4. Remove the two (2) screws holding the rear barrier to the base
plate.
5. Release the three (3) tabs of rear barrier from the base plate. And
remove the rear barrier.
6. Remove the one (1) screw holding the back plate to the base plate.
7. Remove the one (1) screw holding the chassis support to the back
plate.
8. Remove the one (1) screw holding the back plate to the air intake
duct.
9. Remove the two (2) screws holding the back plate to the convec-
tion duct.
10.Remove the back plate from the oven cavity.
11.Disconnect the wire leads from the convection heating elements,
convection motor and thermal cut-out.
12.Remove the one (1) screw holding the convection duct to the oven
cavity back plate from outside of the oven cavity.
Gap
Rotor
Bracket
Stator
Groove joint pliers
Coil
Shaft
Axis
Stator
Rotor
These are the positions
that should be pinched
with pliers.
Shaft
Table
Center of
bracket
Rear View
Side View
Cutting pliers
Turntable
motor cover
Bridges
Base plate
Turntable
motor cover
Tab
Screw: XHPS740P08K00
Base plate
Slit
R98STMAA
11 – 4
13.Remove the seven (7) screws holding the convection duct to the
oven cavity back plate from inside of the oven cavity.
14.Lift up the convection duct and release the three (3) tabs of the
oven cavity back plate from the convection duct.
15.Now, the convection unit assembly is free.
2. CONVECTION HEATING ELEMENT REMOVAL
1. Remove the convection unit assembly refer to the “CONVECTION
UNIT ASSEMBLY REMOVAL”.
2. Remove the two (2) screws holding the convection heating element
to the convection duct.
3. Remove the one (1) screw holding the convection heater angle to
the convection duct.
4. Remove the one (1) screw holding the convection heater angle and
the air separate angle D to the convection duct.
5. Remove the one (1) screw holding the convection heater angle A to
the convection duct.
6. Remove the convection heating element from the convection duct.
7. Now, the convection heating element is free.
3. CONVECTION MOTOR REMOVAL
1. Remove the convection unit assembly refer to the “CONVECTION
UNIT ASSEMBLY REMOVAL”.
2. Remove the one (1) nut and washer from the convection motor
shaft.
3. Remove the convection fan from the convection motor shaft.
4. Remove the pipe from the convection motor shaft. 
5. Remove the two (2) screws holding the convection motor angle to
the convection duct.
6. Remove the cooling fan from the convection motor shaft.
7. Remove the two (2) screws holding the convection motor to the
convection motor angle.
8. Remove the one (1) ring from the convection motor shaft.
9. Now, the convection motor is free.
[10] POSITIVE LOCK CONNECTOR REMOVAL
1. CARRY OUT 3D CHECKS.
2. Push the lever of positive lock
 connector.
3. Pull down on the positive lock
 connector.
CAUTION: WHEN CONNECTING THE POSITIVE LOCK
 CONNEC-
TORS TO THE TERMINALS, CONNECT THE POSITIVE
LOCK
 SO THAT THE LEVER FACES YOU.
Figure C-3. Positive lock
, connector
[11] OVEN LAMP SOCKET REMOVAL
1. CARRY OUT 3D CHECKS.
2. Remove the wire leads as Positive lock
 connector removal above.
3. Lift up the oven lamp from its retaining clips by pushing the tab of
the air intake duct.
4. Now, the oven lamp is free.
Figure C-4. Oven lamp
[12] POWER SUPPLY CORD REPLACEMENT
1. REMOVAL
1. CARRY OUT 3D CHECKS.
2. Remove the one (1) screw holding the green/yellow wire to the
back plate.
3. Disconnect the leads of the power supply cord from the noise filter,
referring to the Figure C-5(a).
4. Release the power supply cord from the rear cabinet.
5. Now, the power supply cord is free.
Figure C-5 (a) Replacement of Power Supply Cord
Terminal
Push
Pull down
1
2
Lever
Positive lock¨
connector
Lock
Socket
Bulb
Power supply
cord
Back plate
Blue wire
Brown wire
Green/
Yellow wire
Noise filter
WHIT
RED
F2
F1
TP
N
L
TL
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