Read Sharp R-22AMM (serv.man8) Service Manual online
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.
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.
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.
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.
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.
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.
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.
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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