DOWNLOAD Sharp R-872M (serv.man3) Service Manual ↓ Size: 393.96 KB | Pages: 21 in PDF or view online for FREE

Model
R-872M (serv.man3)
Pages
21
Size
393.96 KB
Type
PDF
Document
Service Manual
Brand
Device
Home Appliance / Microwave Oven / Part 2 Description of LSI, Schematic diagrams, PWB assemlbiesPage 18-38
File
r-872m-sm3.pdf
Date

Sharp R-872M (serv.man3) Service Manual ▷ View online

R-872M - 21
Pin No.
Signal
I/O
Description
82-90
SEG8-SEG0
OUT
Segment data signal.
Connected to LCD. Signal is similar to SEG39.
91
VCC
IN
Connected to GND.
92
VREF
IN
Connected to GND.
93
AVSS
IN
Connected to VC.
94
COM3
OUT
Terminal not used.
95
COM2
OUT
Common data signal: COM3.
Connected to LCD (Pin No. 35).
96
COM1
OUT
Common data signal: COM2.
Connected to LCD (Pin No. 34).
97
COM0
OUT
Common data signal: COM1.
Connected to LCD (Pin No. 33).
98-99
VL3-VL2
IN
Power source voltage input terminal.
Standard voltage for LCD.
100
C2
IN
Terminal not used.
  DESCRIPTION OF LSI
LSI(IZA965DR)
The I/O signal of the LSI(IZA965DR) are detailed in the following table.
R-872M - 22
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 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. Shapes of Electronic Components
3. 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
supply of the oven :
CAUTION:
THE HIGH VOLTAGE TRANSFORMER OF THE
MICROWAVE OVEN IS STILL LIVE DURING
SERVICING AND PRESENTS A HAZARD .
T
herefore, 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.
  SERVICING
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, therefore, 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 brings about
an operational state that is equivalent to the oven door
being closed. As for the sensor-related controls of the
touch control panel, checking them is possible if the
dummy resistor(s) with resistance equal to that of the
controls are used.
(2) Servicing the touch control panel with power
supply 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 brings about an operational state that is equiva-
lent to the oven door being closed. Connect an exter-
nal 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).
4. Servicing Tools
Tools required to service the touch control panel assem-
bly.
1) Soldering iron: 30W
(It is recommended to use a soldering iron with a
grounding terminal.)
2) Oscilloscope: Single beam, frequency range: DC -
10MHz type or more advanced model.
3) Others: Hand tools
5. 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 connector 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 abnor-
mal 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
precision is required.
E
C B
Transistor
2SB1238
Transistor
KRC243M
E
C
B
approx. 1M ohm
R-872M - 23
9. Discharge the H.V. capacitor before carrying out any
further work.
10.Do not operate the oven with the outer case removed.
N.B.; Step 1, 2 and 9 form the basis of the 3D checks.
CAUTION: DISCHARGE HIGH VOLTAGE CAPACI-
TOR BEFORE TOUCHING ANY OVEN
COMPONENT OR WIRING.
CAUTION: WHEN THE OUTER CASE CABINET IS
RE-INSTALLED, INSTALL IT BEFORE THE
BACK PLATE IS INSTALLED, OR THE
OUTER CASE CABINET WILL BE DE-
FORMED.
  COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE
WARNING: Avoid possible exposure to microwave energy. Please follow the instructions below
before operating the oven.
1. Disconnect oven from power supply.
2. Make sure that a definite “click” can be heard when the
microwave oven door is unlatched. (Hold the door in a
closed position with one hand, then push the door open
button 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 dam-
age (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 or 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.
Please refer to ‘OVEN PARTS, CABINET PARTS, CONTROL PANEL PARTS, DOOR PARTS’, when carrying out any
of the following removal procedures:
WARNING FOR WIRING
To prevent an electric shock, take the following
manners.
1. Before wiring,
1) Disconnect the 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 volt-
age capacitor and High voltage rectifier assem-
bly.
2) Hot parts:
Top heating element, Bottom heating element,
Oven lamp, Magnetron, High voltage transformer
and Oven cavity.
3) Sharp edge:
Bottom plate, Oven cavity, Weveguide flange,
Chassis support and other metallic plate.
4) Movable parts (to prevent a fault)
Fan blade, Fan motor, Switch, Open lever, Open
button,Turntable motor, Convection motor.
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, referring to the Pictorial Diagram.
voltage capacitor.
3. Disconnect the high voltage wire B from the magnetron.
4. Remove one (1) screw holding earth side terminal of
the high voltage rectifier assembly.
OUTER CASE REMOVAL
To remove the outer case proceed as follows.
1. Disconnect oven from power supply.
2. Open the oven door and wedge it open.
3. Remove the two (2) screws holding the back plate to
the oven cavity rear plate. Remove the back plate
4. Remove the one (1) screw holding the air duct assem-
bly to the oven cavity rear plate.
5. Remove the air duct assembly
6. Remove the eight (8) screws from rear and along the
side edge of case.
7. Slide the entire case back about 3 cm to free it from
retaining clips on the cavity face plate.
8. Lift the entire case from the oven.
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 trans-
former and the high voltage wire A from the high
R-872M - 24
HIGH VOLTAGE TRANSFORMER REMOVAL
1. CARRY OUT 3D CHECKS.
2. Disconnect the filament leads of high voltage trans-
former from high voltage capacitor and the magnetron.
3. Disconnect the H.V. wire A from the high voltage
transformer.
4. Disconnect the main wire harness from the high volt-
age transformer.
5. Remove the two (2) screws and one (1) washer holding
the transformer to the base plate.
7. Remove the transformer.
8. Now the high voltage transformer is free.
1. CARRY OUT 3D CHECKS.
2. Disconnect the H.V. wire B and filament lead of the
transformer from the magnetron.
3. Remove the one (1) screw holding the chassis support
to the magnetron.
4. Move the air intake duct to left.
5. Carefully remove four (4) screws holding the magnetron
to the waveguide, when removing the screws hold the
magnetron to prevent it from falling.
6. Remove the magnetron from the waveguide with care
so the magnetron antenna is not hit by any metal object
around the antenna.
CAUTION: WHEN REPLACING THE MAGNETRON,
BE SURE THE R.F. GASKET IS IN PLACE
AND THE MAGNETRON MOUNTING
SCREWS ARE TIGHTENED SECURELY.
             MAGNETRON REMOVAL
adhesive on the control panel frame surfaces com-
pletely 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
rubbing with soft cloth not to scratch.
1. CARRY OUT 3D CHECKS.
2. Disconnect the wire leads and the connectors from the
control unit.
3. 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
CONTROL PANEL ASSEMBLY REMOVAL
FAN MOTOR REPLACEMENT
the gap between the rotor & startor 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.
2) Remove the fan blade assembly from the shaft of
the fan motor by pulling and rotating the fan blade
with your hand.
3) Now, the fan blade is free.
CAUTION:
• Do not  reuse the removed fan blade as the
fixing hole  may be oversize.
12.Remove the two (2) screws and nuts holding the fan
motor to the fan duct.
13.Now, the fan motor is free.
INSTALLATION
1. Install the 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.
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 one (1) screw holding the chassis support
to the oven cavity front flange.
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 capacitor holder
to the oven cavity back plate.
8. Release the tabs of the capacitor holder from the fan
duct.
9. Remove the one (1) screw holding the fan duct to the
oven cavity back plate.
10.Remove the fan duct from the oven.
11.Remove the fan duct from the fan motor shaft accord-
ing to the following procedure.
1) 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
5. Remove one (1) screw holding fan duct to the oven
cavity rear plate.
6. Remove one (1) screw holding capacitor holder to the
oven cavity rear plate.
7. Release the capacitor holder from the fan duct.
8. Remove the high voltage capacitor from the capacitor
holder.
9. Disconnect the high voltage wire B and the high voltage
rectifier assembly from the high voltage capacitor.
10.Disconnect the high voltage rectifier assembly from the
high voltage wire B.
11.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 CAPACI-
TOR HOLDER WITH AN EARTHING
SCREW.
  COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE
Page of 21
Display

Sharp R-872M (serv.man3) Service Manual ▷ Download

  • DOWNLOAD Sharp R-872M (serv.man3) Service Manual ↓ Size: 393.96 KB | Pages: 21 in PDF or view online for FREE
  • Here you can View online or download the Service Manual for the Sharp R-872M (serv.man3) in PDF for free, which will help you to disassemble, recover, fix and repair Sharp R-872M (serv.man3) Microwave Oven. Information contained in Sharp R-872M (serv.man3) Service Manual (repair manual) includes:
  • Disassembly, troubleshooting, maintenance, adjustment, installation and setup instructions.
  • Schematics, Circuit, Wiring and Block diagrams.
  • Printed wiring boards (PWB) and printed circuit boards (PCB).
  • Exploded View and Parts List.