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 - 19
Pin No.
Signal
I/O
Description
26
P40
OUT
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P44 - P47 terminal
while one of G7 line key on matrix is touched.
27
P77
OUT
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P44 - P47 terminal
while one of G6 line key on matrix is touched.
28
P76
OUT
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P44 - P47 terminal
while one of G5 line key on matrix is touched.
29
P75
OUT
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P44 - P47 terminal
while one of G4 line key on matrix is touched.
30
P74
OUT
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P44 - P47 terminal
while one of G3 line key on matrix is touched.
31
P73
OUT
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P44 - P47 terminal
while one of G2 line key on matrix is touched.
32
P72
OUT
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P44 - P47 terminal
while one of G1 line key on matrix is touched.
33
P71
OUT
Oven lamp and turntable motor driving signal(Square Waveform : 50Hz).
To turn on and off shut-off relay (RY1).
The square waveform voltage is
delivered to the relay (RY1) driving
circuit.
34
P70
IN
Connected to VC.
35
RESET
IN
Auto clear terminal.
Signal is input to reset the LSI to the initial state when power is applied. Temporarily
set to "L" level the moment power is applied, at this time the LSI is reset. Thereafter
set at "H" level.
36
P81
OUT
Magnetron high-voltage circuit driving signal.
To turn on and off the cook relay
(RY2). In 100% operation, the
signals hold "L" level during
microwave cooking and "H" level
while not cooking. In other
cooking modes (70%, 50%, 30%,
10%) the signal turns to "H" level
and "L" level in repetition
according to the power level.
37
P80
OUT
Grill (TOP) heating element driving signal.
To turn on and off the grill heating
element relay (RY3). "L" level during
grill cooking, convection cooking or
dual cooking, "H" level otherwise.
The heater relay turns on and off
within a 48 second time base in
accordance with the special program
in LSI.
38
XIN
IN
Internal clock oscillation frequency input setting.
The internal clock frequency is set by inserting the ceramic filter oscillation circuit
with respect to XIN terminal.
ON/OFF time ratio in Mi-
cro cooking
(a. 32second time base)
ON/OFF time ratio in Mi-
cro cooking
(a. 48second time base)
MICRO
ON
OFF
COOK
100%
32 sec.
0 sec.
70%
24 sec.
8 sec.
50%
18 sec. 14 sec.
30%
12 sec. 20 sec.
10%
6 sec. 26 sec.
MICRO
ON
OFF
COOK
100%
48 sec.
0 sec.
70%
36 sec. 12 sec.
50%
26 sec. 22 sec.
30%
16 sec. 32 sec.
10%
8 sec. 40 sec.
Power output
ON time
OFF time
100 %
48 sec.
0 sec.
90 %
44 sec.
4 sec.
80 %
40 sec.
8 sec.
70 %
36 sec.
12 sec.
60 %
32 sec.
16 sec.
50 %
26 sec.
22 sec.
40 %
22 sec.
26 sec.
30 %
16 sec.
32 sec.
20 %
12 sec.
36 sec.
10 %
8 sec.
40 sec.
During cooking
L
H
20 msec.
  DESCRIPTION OF LSI
LSI(IZA965DR)
The I/O signal of the LSI(IZA965DR) are detailed in the following table.
R-872M - 20
39
XOUT
OUT
Internal clock oscillation frequency control output.
Output to control oscillation input of XOUT.
40
VSS
IN
Power source voltage: -5V.
VC voltage of power source circuit input.
41
P27
OUT
Bottom heating element driving signal.
To turn on and off the relay (RY4). "L"
level during grill cooking, convection
cooking or dual cooking, "H" level
otherwise.
The heater relay turns on and off within
a 48 second time base in accordance
with the special program in LSI.
42
P26
OUT
Convection motor driving signal.
To turn on and off shut-off relay(RY7). "L"
level during convection or dual cooking "H"
level otherwise. (Relay RY7 does not turn on
at preheating mode.)
43
P25
OUT
Fan motor driving signal.
To turn on and off the fan motor relay RY6.  "L"
level during cooking, or for 5 minutes after grill
cooking or for a while after convection or dual
cooking. "H" level otherwise.
44
P24
OUT
Terminal not used.
45
P23
OUT
Touch control transformer driving signal.
To turn on and off the shut off relay (RY5). If the oven has not been used for more
than 2 minutes, the relay RY5 will be turned off. The relay RY5 will be turned on
when the oven door is opened and closed.
46-47
P22-P21
OUT
Terminal not used.
48
P20
OUT
Terminal not used.
49-50
P17-P16
IN
Terminal to change functions according to the model.
51-80
SEG39-SEG10
OUT
Segment data signal.
Connected to LCD.
The relation between signals are as follows:
LSI signal (Pin No.)
LCD (Pin No.)
LSI signal (Pin No.) LCD (Pin No.)
SEG 0 (90) ....................SEG39 (51)
SEG21 (69) ................. SEG19 (19)
SEG 1 (89) ....................SEG38 (50)
SEG22 (68) ................. SEG18 (18)
SEG 2 (88) ....................SEG37 (49)
SEG23 (67) ................. SEG17 (17)
SEG 3 (87) ....................SEG36 (48)
SEG24 (66) ................. SEG16 (16)
SEG 4 (86) ....................SEG35 (47)
SEG25 (65) ................. SEG15 (15)
SEG 5 (85) ....................SEG34 (46)
SEG26 (64) ................. SEG14 (14)
SEG 6 (84) ....................SEG33 (45)
SEG27 (63) ................. SEG13 (13)
SEG 7 (83) ....................SEG32 (44)
SEG28 (62) ................. SEG12 (12)
SEG 8 (82) ....................SEG31 (43)
SEG29 (61) ................. SEG11 (11)
SEG10 (80) ................... SEG30 (30)
SEG30 (60) ................. SEG10 (10)
SEG11 (79) ................... SEG29 (29)
SEG31 (59) ................... SEG 9 ( 9)
SEG12 (78) ................... SEG28 (28)
SEG32 (58) ................... SEG 8 ( 8)
SEG13 (77) ................... SEG27 (27)
SEG33 (57) ................... SEG 7 ( 7)
SEG14 (76) ................... SEG26 (26)
SEG34 (56) ................... SEG 6 ( 6)
SEG15 (75) ................... SEG25 (25)
SEG35 (55) ................... SEG 5 ( 5)
SEG16 (74) ................... SEG24 (24)
SEG36 (54) ................... SEG 4 ( 4)
SEG17 (73) ................... SEG23 (23)
SEG37 (53) ................... SEG 3 ( 3)
SEG18 (72) ................... SEG22 (22)
SEG38 (52) ................... SEG 2 ( 2)
SEG19 (71) ................... SEG21 (21)
SEG39 (51) ................... SEG 1 ( 1)
SEG20 (70) ................... SEG20 (20)
81
SEG9
OUT
Terminal not used.
Pin No.
Signal
I/O
Description
ON
OFF
During
cooking
L
GND
H.
(Convection or dual cooking)
ON
OFF
During cooking or for 5 minutes after
grill, or for awhile after convection or dual. 
L
GND
H.
Power output
ON time
OFF time
100 %
48 sec.
0 sec.
90 %
44 sec.
4 sec.
80 %
40 sec.
8 sec.
70 %
36 sec.
12 sec.
60 %
32 sec.
16 sec.
50 %
26 sec.
22 sec.
40 %
22 sec.
26 sec.
30 %
16 sec.
32 sec.
20 %
12 sec.
36 sec.
10 %
8 sec.
40 sec.
  DESCRIPTION OF LSI
LSI(IZA965DR)
The I/O signal of the LSI(IZA965DR) are detailed in the following table.
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
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  • 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.