R-8000G
28
Memory Processor (IC-2)
Memory processor is a 16K-bit, serial memory, enabling CMOS to be erased/written electrically. This memory is constructed with 2048
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-3 Relation between Pin Nos, and Signals
Pin No.
Signal
I/O
Description
1-3
A0-A2
IN
Connected to -5V.
4
VSS
IN
Connected to -5V.
5
SDA
IN/OUT
Serial data input/output : input/outputs data to IC1.
6
SCL
IN
Clock signal input : input/outputs sireal data at every one pulse.
7
WP
IN
Connected to -5V.
8
VCC
IN
Connected to GND.
A0
A1
A2
VSS
VCC
WP
SCL
SDA
TOP VIEW
1
2
3
4
8
7
6
5
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 imped-
ance 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 some-
times 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 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 external 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, 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 trans-
former.
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 trans-
former.
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
approx. 1M ohm
