DOWNLOAD Sharp R-22AMM (serv.man8) Service Manual ↓ Size: 217.67 KB | Pages: 5 in PDF or view online for FREE

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R-22AMM (serv.man8)
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Service Manual
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Device
Home Appliance / Microwave Oven / Touch Control Panel Assembly
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r-22amm-sm8.pdf
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Sharp R-22AMM (serv.man8) Service Manual ▷ View online

R22AMM
8 – 1
R22AMM
Service Manual
 
CHAPTER 8. 
TOUCH CONTROL PANEL ASSEMBLY
[1] OUTLINE OF TOUCH CONTROL PANEL 
The touch control section consists of the following units as shown in
the touch control panel circuit.
(1) Control Unit
(2) Switch Unit
(3) Encoder Unit
The principal functions of these units and the signals communicated
among them are explained below.
1. Control Unit
Signal of key touch and oven function control are all processed by one
microcomputer.
1) Power Supply Circuit
This circuit changes output voltage at the secondary side of the
touch control transformer to voltages required at each part by full
wave rectifying circuit, constant voltage circuit, etc..
2) Reset Circuit
This is an Auto-clear Circuit, i.e., a reset circuit, which enables IC1
to be activated from initial state.
3) Power Synchronizing Signal Generating Circuit
This is a circuit for generating power synchronizing signal by virtue
of the secondary side output of touch control transformer. This sig-
nal is used for a basic frequency to time processing and so on.
4) Clock Circuit
This is a circuit for controlling clock frequency required for operat-
ing I-1.
5) I-1 (Main Processor)
This is a one-chip microcomputer, responsible for controlling the
entire control unit.
6) I-2 (Memory Processor)
This is a memory IC, responsible for memory function. 
7) Display Circuit
This is a circuit for driving display tubes by I-1 output.
8) Switch Input Circuit
This is a circuit for transmitting switch input information to I-1.
9) Sound-body Driving Circuit
This is a circuit for driving sound body by I-1 output.
10)Relay Driving Circuit
This is a circuit for driving output relay by I-1 output.
11)Stop Switch Circuit
This is a circuit for driving I-1 to detect door opening/ closing.
12)Exhaust Air Temperature Detecting Circuit
This is a circuit for transmitting output change of thermistor
(Exhaust thermistor) to I-1.
13)Magnetron Temperature Circuit. (Detect No-load or Fan Lock)
This is a circuit for transmitting output change of thermistor (Mag-
netron thermistor) to I-1.
14)High Voltage Monitoring Circuit.
This circuit detects problems in the magnetron / high voltage circuit
by sensing a variation in the current flowing through the primary
winding of the high voltage transformer. During heating, the primary
current of the high voltage transformers also flows through the pri-
mary winding of the current transformer.
This causes a current to be induced in the secondary windings of
current transformer and results in an AC voltage which is deter-
mined. 
This AC voltage is then half wave rectified and smoothed (filtered).
This AC voltage is the input to the AN3 port of IC1, which deter-
mines if there is a magnetron / high voltage problem.
2. Switch Unit
The switch unit is composed of a matrix circuit in which when a switch
it touched, one of signals P30 - P31 generated by the LSI, is passed
through the switch and returned to the LSI as one of signals P24 - P26.
3. Encoder
The encoder converts the signal generated by power source circuit
into the pulse signal, and the pulse signal is sent to the LSI.
[2] DESCRIPTION OF LSI
1. LSI
The I/O signal of the LSI(IXA499DR) is detailed in the following table.
Pin No. 
 Signal 
 I/O 
 Description 
1
VCC
IN
Power source voltage: GND. 
VC voltage of power source circuit input. Connected to GND.
2
VEE
IN
Anode (segment) of Fluorescent Display light-up voltage: -35V. 
Vp voltage of power source circuit input.
3
AVSS
IN
Reference voltage input terminal. 
A reference voltage applied to the A/D converter in the LSI. Connected to DC. (-5V)
4
VREF
IN
Reference voltage input terminal. 
A reference voltage applied to the A/D converter in the LSI. Connected to GND.
5-6
AN7-AN6
IN
Terminal to switch the specification.
7
AN5
IN
Temperature measurement input: EXHAUST THERMISTOR 
By inputting DC voltage corresponding to the temperature detected by the thermistor, this input is converted into 
temperature by the A/D converter built into the LSI.
8
AN4
IN
Input signal which communicates the door open/close information to LSI. 
Door closed; “H” level signal (0V). Door opened; “L” level signal (-5.0V).
9
AN3
IN
A/D input for troubleshooting of high voltage circuits.
R22AMM
8 – 2
10
AN2
IN
Temperature measurement input: MAGNETRON THERMISTOR TH2.
By inputting DC voltage corresponding to the temperature detected by the thermistor, this input is converted into 
temperature by the A/D converter built into the LSI.
11
AN1
IN
Temperature measurement input: MAGNETRON THERMISTOR TH1. 
By inputting DC voltage corresponding to the temperature detected by the thermistor, this input is converted into 
temperature by the A/D converter built into the LSI.
12
AN0
-
Terminal not used.
13-14
P55-P54
-
Terminal not used.
15
P53
OUT
Magnetron (MG1) high-voltage circuit driving signal. 
To turn on and off the cook relay. In 100% power level operation, “L” level during cooking; “H” level otherwise. In 
other power level operation (50, 20 or 10%), “H” and “L” level is repeated according to power level.
16
P52
-
Terminal not used.
17
P51
OUT
Magnetron (MG2) high-voltage circuit driving signal.
To turn on and off the cook relay. In 100% power level operation, “L” level during cooking; “H” level otherwise. In 
other power level operation (50, 20 or 10%), “H” and “L” level is repeated according to power level.
18
P50
-
Terminal not used.
19
P47
OUT
Signal to sound buzzer. 
This signal is to control the 2.0kHz continuous signal. 
A: Switch touch sound. 
B: Completion sound.
20-21
P46-P45
-
Terminal not used.
22
P44
OUT
Oven lamp, Blower motor and Antenna motor driving signal (Square Wave-form: 50Hz).
To turn on and off the shut-off relay (RY1). The Square 
waveform voltage is delivered to the RY1 relay driving cir-
cuit and relays (RY3, RY4, COOK RELAY) control circuit.
23
P43
-
Terminal not used.
24
P42
IN
Signal coming from encoder. 
When the encoder is turned, the contacts of encoder make pulse signals. And pulse signals are input into P42.
25
INT1
IN
Signal synchronized with commercial power source frequency.OFF 
 This is basic timing for all time processing of LSI.
26
INT0
IN
Signal coming from encoder.
Signal similar to P42. Pulse signals are input into INT0.
27
RESET
IN
Auto clear terminal.
Signal is input to reset the LSI to the initial state when power is supplied. Temporarily set to “L” level the moment 
power is supplied, at this time the LSI is reset. Thereafter set at “H” level.
28
P71
OUT
Memory (EEPROM) clock output.
29
P70
IN/OUT Memory (EEPROM) data input/output.
30
XIN
IN
Internal clock oscillation frequency setting input.
The internal clock frequency is set by inserting the ceramic filter oscillation circuit with respect to XOUT terminal.
Pin No. 
 Signal 
 I/O 
 Description 
GND
-5V
48 sec.
OFF
ON
Power level
ON
OFF
100%
48sec.
0sec.
50%
26sec. 22sec.
20%
12sec. 36sec.
10%
8sec. 40sec.
GND
-5V
48 sec.
OFF
ON
Power level
ON
OFF
100%
48sec.
0sec.
50%
26sec. 22sec.
20%
12sec. 36sec.
10%
8sec. 40sec.
A
B
0.12 sec
2.4 sec
GND
-5V
H
L
20 msec
During cooking
GND
-5V
20 msec.
OFF
ON
R22AMM
8 – 3
31
XOUT
OUT
Internal clock oscillation frequency control output.
Output to control oscillation input of XIN.
32
VSS
IN
Power source voltage: -5V. 
VC voltage of power source circuit input.
33
P27
-
Terminal not used.
34
P26
IN
Signal coming from switch unit.
When either one of G-1 line switches on switch matrix is touched, a corresponding signal out of P30 - P31 will be 
input into P26. When no switch is touched, the signal is held at “L” level.
35
P25
IN
Signal similar to P26.
When either one of G-2 line switches on switch matrix is touched, a corresponding signal will be input into P25.
36
P24
IN
Signal similar to P26.
When either one of G-3 lines witches on switch matrix is touched, a corresponding signal will be input into P24.
37-40
P23-P20
OUT
Segment data signal.
The relation between signals and indicators are as follows:
Signa    Segment    Signal    Segment    Signal    Segment
  P01 -------------- k         P21 -------------- h           P15 -------------- d
  P02 -------------- j          P20 -------------- g          P14 -------------- c
  P03 -------------- i          P17 -------------- f           P13 -------------- b
  P23 ------------ LB         P16 -------------- e          P12 -------------- a
  P22 ------------ UB
41-46
P17-P12
OUT
Segment data signal.
Signal similar to P23.
47-48
P11-P10
OUT
Digit selection signal. 
 The relation between digit signal and digit are as follows
 Digit signal               Digit 
     P11 .................... 1st.
     P10 ................... 2nd. 
     P07 .................... 3rd
     P06 .................... 4th. 
     P05 .................... 5th.
     P04 .................... 6th. 
Normally, one pulse is output in every 
 period, and input to 
the grid of the Fluorescent Display.
49-52
P07-P04
OUT
Digit selection signal.
Signal similar to P11
53-55
P03-P01
OUT
Segment data signal. 
 Signal similar to P23.
56
P00
-
Terminal not used.
57-58
P37-P36
OUT
(Sound) Voltage level control terminal.
This terminal (P37) is to control volume level of buzzer sound with terminals P36. Since the volume level of buzzer 
sound depends on voltage energized, it is control level in 3 steps by combining signal levels for P37 and P36. 
Relationship of signal level combination to sound volume level is shown in the following table, 1~3 in the table, 
however, are indicated in the descending order from the maximum level of sound volume through the minimum 
level.
*At Output terminal P47, rectangular wave signal of 2.5kHz is output.
59
P35
-
Terminal not used.
60
P34
OUT
Terminal not used.
61
P33
OUT
Terminal not used.
62
P32
OUT
Terminal not used.
63
P31
OUT
Switch strobe signal.
Signal applied to switch unit section. A pulse signal is input to P24 - P26 terminals while one of G-4 line switches 
on switch matrix is touched.
64
P30
OUT
Switch strobe signal.
Signal applied to switch unit section. A pulse signal is input to P24 - P26 terminals while one of G-5 line switches 
on switch matrix is touched.
Pin No. 
 Signal 
 I/O 
 Description 
GND
-31(V)
ß
(50Hz)
H
L
GND
ß
(50Hz)
ß
P11
P10
P07
P06
P05
P04
GND
-31(V)
-31(V)
A
A : 1,(Max) 20V
2,
13V
3,(Min)
7V
Sound Volume P36
P37
1, (Max.)
L
L
2,
H
L
3, (Min.)
L
H
R22AMM
8 – 4
2. Memory IC (I-2)
CAT24WC16PI is a 16K-bit, serial memory, enabling CMOS to be erased/written electrically. This memory is constructed with 512 registers x 8bits,
enabling individual access, read and write operations to be performed. Details of input/output signal for IC2 are as shown in the following diagram.
Figure T-2. Relation between Pin Nos, and Signals
[3] SERVICING FOR TOUCH CONTROL PANEL
1. Precautions for Handling Electronic Components
This unit uses CMOS LSI in the integral part of the circuits. When han-
dling these parts, the following precautions should be strictly followed.
CMOS LSI have extremely high impedance at its input and output ter-
minals. 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. 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 precautions 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 exter-
nal power source.
1. Servicing the touch control panel with power supply of the
oven:
CAUTION: THE HIGH VOLTAGE TRANSFORMER OF THE MICRO-
WAVE OVEN IS STILL LIVE DURING SERVICING AND
PRESENTS A HAZARD.
Therefore, when checking the performance of the touch control
panel, put the outer cabinet on the oven to avoid touching the high
voltage transformer, or unplug the primary terminal (connector) of
the high voltage transformer to turn it off; the end of such connector
must be insulated with an insulating tape. After servicing, be sure to
replace the leads to their original locations.
i)
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.
ii) 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 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:
 Pin No.   Signal 
 I/O 
 Description 
 1-3 
 A0-A2 
 IN 
 Connected to GND. 
 4 
 VSS 
 IN 
 Connected to VC(-5V). 
 5 
 SDA 
 IN/OUT 
 Serial data input/output: input/outputs data to I-1. 
 6 
 SCL 
 IN 
 Clock signal input: input/outputs serial data at every one pulse. 
 7 
 TEST 
 IN 
 Connected to VC(-5V). 
 8 
 VCC 
 IN 
 Connected to GND. 
FUNCTIONAL DIAGRAM
E PROM
512 x 8
2
START
STOP
LOGIC
CONTROL
LOGIC
SLAVE ADDRESS
REGISTER
COMPARATOR
H.V. GENERATION
TIMING
& CONTROL
64
YDEC
8
DATA REGISTER
Dout
CK
3
1
5
64
XDEC
START CYCLE
INC
LOAD
WORD
ADDRESS
COUNTER
R/W
PIN
Dout
ACK
(6) SCL
(5) SDA
(4) Vss
(3) Vcc
A0
8
1
7
2
6
3
5
4
A1
A2
VSS
VCC
TEST
SCL
SDA
TOP VIEW
approx. 1M ohm
3
2
1
E
C
B
E C
B
Transistor
KIA79L05P
DTB143ES
DTD143ES
KRA101M
Transistor
2SB953
Transistor
2SB1238
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  • Here you can View online or download the Service Manual for the Sharp R-22AMM (serv.man8) in PDF for free, which will help you to disassemble, recover, fix and repair Sharp R-22AMM (serv.man8) Microwave Oven. Information contained in Sharp R-22AMM (serv.man8) 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.