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Model
R-8000GK
Pages
44
Size
1.16 MB
Type
PDF
Document
Service Manual
Brand
Device
Home Appliance / Microwave Oven
File
r-8000gk.pdf
Date

Sharp R-8000GK Service Manual ▷ View online

R-8000GK
19
TOUCH CONTROL PANEL SERVICING
1. Precautions for Handling Electronic Components
This unit uses CMOS LSI in the integral part of the circuits.
When handling these parts, the following precautions
should be strictly followed. CMOS LSI have extremely
high impedance at its input and output terminals. For this
reason, it is easily influenced by the surrounding high
voltage power source, static electricity charge in clothes,
etc. and sometimes it is not fully protected by the built-in
protection circuit.
In order to protect CMOS LSI.
1) When storing and transporting, thoroughly wrap them in
aluminium foil. Also wrap all PW boards containing them
in aluminium foil.
2) When soldering, ground the technician as shown in the
figure and use grounded soldering iron and work table.
2. Servicing of Touch Control Panel
We describe the procedures to permit servicing of the
touch control panel of the microwave oven and the pre-
cautions you must take when doing so. To perform the
servicing, power to the touch control panel is available
either from the power line of the oven itself or from an
external power source.
(1) Servicing the touch control panel with power sup-
ply of the oven:
CAUTION:
THE HIGH VOLTAGE TRANSFORMER OF THE MI-
CROWAVE OVEN IS STILL LIVE DURING SERVIC-
ING AND  PRESENTS A HAZARD.
Therefore, before checking the performance of the touch
control panel,
1) Disconnect the power supply cord, and then remove
outer case.
2) Open the door and block it open.
3) Discharge high voltage capacitor.
4) Disconnect the leads to the primary of the power
transformer.
5) Ensure that these leads remain isolated from other
components and oven chassis by using insulation
tape.
6) After that procedure, re-connect the power supply cord.
After checking the performance of the touch control panel,
1) Disconnect the power supply cord.
2) Open the door and block it open.
3) Re-connect the leads to the primary of the power
transformer.
4) Re-install the outer case (cabinet).
5) Re-connect the power supply cord after the outer case
is installed.
6) Run the oven and check all functions.
A. On some models, the power supply cord between the touch
control panel and the oven itself is so short that the two can’t
be separated. For those models, check and repair all the
controls (sensor-related ones included) of the touch control
panel while keeping it connected to the oven.
B. On some models, the power supply cord between the
touch control panel and the oven proper is long enough
that they may be separated from each other. For those
models, it is possible to check and repair the controls of
the touch control panel while keeping it apart from the
oven proper; in this case you must short both ends of the
door sensing switch (on PWB) of the touch control panel
with a jumper, which activates an operational state that is
equivalent to the oven door being closed. As for the
sensor-related controls of the touch control panel, check-
ing them is possible if dummy resistor(s) with resistance
equal to that of the controls are used.
(2) Servicing the touch control panel with power sup-
ply from an external power source:
Disconnect the touch control panel completely from the
oven proper, and short both ends of the door sensing
switch (on PWB) of the touch control panel, which acti-
vates an operational state that is equivalent to the oven
door being closed. Connect an external power source to
the power input terminal of the touch control panel, then
it is possible to check and repair the controls of the touch
control panel it is also possible to check the sensor-
related controls of the touch control panel by using the
dummy resistor(s).
3. Servicing Tools
Tools required to service the touch control panel assem-
bly.
1) Soldering iron: 60W
(It is recommended to use a soldering iron with a ground-
ing terminal.)
2) Oscilloscope: Single beam, frequency range: DC-10MHz
type or more advanced model.
3) Others: Hand tools
4. Other Precautions
1) Before turning on the power source of the control unit,
remove the aluminium foil applied for preventing static
electricity.
2) Connect the connectors of the key unit to the control unit
being sure that the lead wires are not twisted.
3)  After aluminium foil is removed, be careful that abnormal
voltage due to static electricity etc. is not applied to the
input or output terminals.
4) Attach connectors, electrolytic capacitors, etc. to PWB,
making sure that all connections are tight.
5) Be sure to use specified components where high preci-
sion is required.
approx. 1M ohm
R-8000GK
20
PRECAUTIONS FOR USING LEAD-FREE SOLDER
Sn-Ag-Cu
1. Employing lead-free solder
The "Main PWB" of this model employs lead-free solder. This is indicated by the "LF" symbol printed on the PWB and in the service
manual. The suffix letter indicates the alloy type of the solder.
Example:
Indicates lead-free solder of tin, silver and copper.
2. Using lead-free wire solder
When repairing a PWB with the "LF" symbol, only lead-free solder should be used. (Using normal tin/lead alloy solder may result
in cold soldered joints and damage to printed patterns.)
As the melting point of lead-free solder is approximately 40˚C higher than tin/lead alloy solder, it is recommend that a dedicated
bit is used, and that the iron temperature is adjusted accordingly.
3. Soldering
As the melting point of lead-free solder (Sn-Ag-Cu) is higher and has poorer wettability, (flow), to prevent damage to the land of
the PWB, extreme care should be taken not to leave the bit in contact with the PWB for an extended period of time. Remove the
bit as soon as a good flow is achieved. The high content of tin in lead free solder will cause premature corrosion of the bit. To
reduce wear on the bit, reduce the temperature or turn off the iron when it is not required.
Leaving different types of solder on the bit will cause contamination of the different alloys, which will alter their characteristics,
making good soldering more difficult. It will be necessary to clean and replace bits more often when using  lead-free solder. To
reduce bit wear, care should be taken to clean the bit thoroughly after each use.
This oven can display each total operation time (hours) of the top
heating element, the side heating element and the magnetron.
Procedure for checking the total operation time (e.g.
1234 hours) of the top heating element.
STEP
PROCEDURE
DISPLAY
1
SET
2
SET (within 3sec.)
No.
3
PAUSE
No.
4
MICROWAVE x 2
CK-2     1234H
5
STOP/CLEAR
NOTE: 1 To check the total operation time of the magnetron,
touch MICROWAVE once at step 4 above.
NOTE: 2 To check the total operation time of the side heating
element, touch MICROWAVE 3 times at step 4 above.
PROCEDURE FOR CHECKING/ SETTING TOTAL OPERATION TIME
Procedure for setting the total operation time (e.g.
1000 hours) of the top heating element.
STEP
PROCEDURE
DISPLAY
1
SET
2
SET (within 3sec.)
No.
3
PAUSE
No.
4
MICROWAVE x 2
CK-2     1234H
5
SET
CK-2           0H
6
1, 0, 0, 0
CK-2     1000H
7
SET
SAVED
8
(after 1 sec.)
NOTE: 1 To set the total operation time of the magnetron, touch
MICROWAVE once at step 4 above.
NOTE: 2 To set the total operation time of the side heating
element, touch MICROWAVE 3 times at step 4 above.
R-8000GK
21
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.
WARNING AGAINST HIGH VOLTAGE:
COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE
To prevent an electric shock, take the following precau-
tions.
1. Before wiring,
1) Disconnect the oven from power supply.
2) Open the door and wedge the door 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, High voltage fuse and High voltage rectifier
assembly.
2) Hot parts:
Oven lamp, Magnetron, High voltage transformer, Oven
WARNING FOR WIRING
1. Disconnect the oven from power supply.
2. Make sure that a definite” click” can be heard when the
microwave oven door is unlatched. (Pull down the door
handle in a closed position with one hand, then push the
door with the other, this causes the latch leads to rise, it is
then possible to hear a “click’ as the door switches operate.)
3. 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
transmission 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.
cavity and Heating element.
3) Sharp edge:
Bottom plate, Oven cavity, Waveguide flange, Chassis
support and other metallic plate.
4) Moveable parts (to prevent a fault)
Fan blade, Fan motor, Switch, Door cam, Jet motor,
Convection fan, Turntable motor.
3. Do not catch the wire leads in the outer case cabinet.
4. Insert the positive lock connector until its pin is locked and
make sure that the wire leads do not  come off even if the
wire leads are pulled.
5. To prevent an error function, connect the wire leads correctly,
referring to the Pictorial Diagram.
Please refer to ‘OVEN PARTS, CABINET PARTS, CONTROL PANEL PARTS, DOOR PARTS’, when carrying out any of the following
removal procedures:
1. Disconnect the oven from power supply.
2. Open the oven door and wedge the door open.
3. Remove the three (3) screws holding the exhaust cover to the
back plate.
4. Remove the four (4) screws holding the louver cover to the
back plate.
5. Remove the three (3) screws holding the rear side of the outer
case cabinet to the back plate.
6. Remove the four (4) screws holding the right and left sides of
the outer case cabinet to the bottom plate.
7. Slide the entire outer case cabinet back out about 1 inch (3cm)
OUTER CASE REMOVAL
to free it from retaining clips on the oven cavity front plate.
8. Lift entire outer case cabinet from the unit.
9. Discharge the high voltage capacitor before carrying out any
further work.
10. Do not operate the oven with the outer case removed.
N.B.; Step1, 2 and 9 from the basis of the 3D checks.
CAUTION
1. DISCONNECT THE OVEN FROM THE POWER SUPPLY
BEFORE REMOVING THE OUTER CASE CABINET.
2. DISCHARGE THE HIGH VOLTAGE CAPACITOR BEFORE
TOUCHING ANY OVEN COMPONENTS OR WIRING.
OVEN LAMP AND LAMP SOCKET REMOVAL
1. CARRY OUT 3D CHECKS.
2. Pull the wire leads from the oven lamp socket by pushing the
terminal hole of the oven lamp socket with the flat type small
screw driver.
3. Tear the cushion from the light mounting plate.
4. Bend the tab of the light mounting plate holding the oven.
R-8000GK
22
5. Pull out the oven lamp socket.
6. Remove the oven lamp from the oven lamp socket.
7. Now, the oven lamp socket is free.
Figure C-1. Oven lamp socket
1. Open covers of the terminal insulator by using small flat type
screw driver.
2. Remove the receptacle from the terminal insulator.
3. Now, the terminal insulator is free.
TERMINAL INSULATOR REPLACEMENT
Installation
1. Insert the receptacle into terminal insulator.
2. Close covers of the terminal insulator, as shown illustrated
below
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®
CONNECTORS TO THE TERMINALS, CONNECT
THE POSITIVE LOCK® SO THAT THE LEVER
FACES YOU.
POSITIVE LOCK® CONNECTOR (NO-CASE TYPE) REMOVAL
Figure C-3. Positive lock® connector
R
emoval
1. CARRY OUT 3D CHECKS.
2. Remove the one (1) screw holding the green/ yellow wire
of the power supply cord to the bottom plate.
3. Disconnect the blue and brown wire leads of the power
supply cord from the noise filter.
4. Nip the cord bushing with bushing pliers and release it
from the hole of the back plate.
5. Remove the cord bushing from the power supply cord,
and the power supply cord from the back plate.
6. Now, the power supply cord is free.
Reinstall
1. Reinstall the cord bushing to the power supply cord.
2. Insert the power supply cord with the cord bushing into the
hole of the back plate.
3. Hold the green/ yellow wire of the power supply cord to the
bottom plate with the one (1) screw.
4. Reconnect the blue and brown wire leads of the power
supply cord to noise filter, referring to the pictorial diagram.
POWER SUPPLY CORD REPLACEMENT
5. Not to be caught by the outer case cabinet, pass the
green/ yellow wire of the power supply cord under the high
voltage capacitor.
6. Reinstall the outer case cabinet and check that the oven
is operating properly.
Figure C-4. Power supply cord replacement
Flat type
screw driver
Terminal 
insulator
Receptacle
Covers
N
L
Back plate
Bottom plate
Power supply cord
Blue wire
Cord bushing
High voltage
capacitor
Brown wire
Green/ Yellow
wire
Noise filter
Screw
Terminal
Push
Pull down
1
2
Lever
Positive lock®
connector
Figure C-2(a). Terminal insulator
Figure C-2(b). Terminal insulator
BACK PLATE REMOVAL
1. CARRY OUT 3D CHECKS.
2. Remove the one (1) screw holding the green/ yellow wire
of the power supply cord to the bottom plate.
3. Disconnect the blue and brown wire leads wire of the
power supply cord from the noise filter.
4. Remove the three (3) screws holding the back plate to the
bottom plate.
5. Remove the two (2) screws holding the back plate to the
exhaust duct.
6. Remove the two (2) screws holding the right and left
chassis supports to the back plate.
7. Release the tabs of the chassis supports from the back
plate.
8. Now, the back plate with the power supply cord is free.
Oven lamp
socket
Terminal
Wire lead
Terminal hole
Flat type small
screw driver
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