R- 308JK
R - 308JS
R-308JW
R-309JW
17
TEST PROCEDURES
PROCEDURE
LETTER
COMPONENT TEST
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.
7) Follow the troubleshooting guide given below for repair.
STEPS
OCCURRENCE
CAUSE OR CORRECTION
The rated AC voltage is not present between
1
the normal open terminal of the relay RY1 and
Check supply voltage and oven power cord.
the normal open terminal of the relay RY2.
2
The rated AC voltage is present at primary
Low voltage transformer or secondary circuit defective.
side of low voltage transformer.
Check and replace control unit assembly.
8) Disconnect the power supply cord, and then remove outer case.
9) Open the door and block it open.
10) Discharge high voltage capacitor.
11) Reconnect all leads removed from components during testing.
12) Re-install the outer case (cabinet).
13) Reconnect the power supply cord after the outer case is installed.
14) Run the oven and check all functions.
TOUCH CONTROL PANEL ASSEMBLY
OUTLINE OF TOUCH CONTROL PANEL
The touch control section consists of the following units.
(1) Key Unit
(2) Control Unit (The Control Unit consists of Power Unit
and CPU Unit).
The principal functions of these units and the signals commu-
nicated among them are explained below.
Key Unit
The key unit is composed of a matrix, signals generated in the
LSI are sent to the key unit through P22, P23, P24, P25, P26,
P31, P32 and P33.
When a key pad is touched, a signal is completed through the
key unit and passed back to the LSI through P50, P51, P52 and
P53 to perform the function that was requested.
Control Unit
Control unit consists of LSI, reset circuit, indicator circuit, power
source circuit, relay circuit, buzzer circuit, synchronizing signal
circuit and back light circuit.
1) Reset Circuit
This circuit generates a signal which resets the LSI to the
initial state when power is supplied.
2) Indicator Circuit
This circuit consists of 14 segments and 3 common
electrodes using a Liquid Crystal Display.
3) Power Source Circuit
This circuit generates voltages necessary in the control unit
from the AC line voltage.
In addition, the synchronizing signal is available in order to
compose a basic standard time in the clock circuit.
Symbol
Voltage
Application
VSS
-5V
LSI(IC1)
4) Relay Circuit
A circuit to drive the magnetron, fan motor, turntable motor
and light the oven lamp.
5) Buzzer Circuit
The buzzer is responsive to signals from the LSI to emit
audible sounds (key touch sound and completion sound).
6) Synchronizing Signal Circuit
The power source synchronizing signal is available in order
to compose a basic standard time in the clock circuit.
It accompanies a very small error because it works on
commercial frequency.
7) Door Sensing Switch
A switch to “tell” the LSI if the door is open or closed.
8) Back Light Circuit
A circuit to drive the back light (Light emitting diodes LD1-
LD3).
