12
R-312AW
R-312AK
TEST PROCEDURES
PROCEDURE
LETTER
COMPONENT TEST
If the monitor fuse is blown when the door is opened, check the primary interlock switch and monitor
switch according to the "TEST PROCEDURE" for those switches before replacing the blown monitor
fuse.
CAUTION: BEFORE REPLACING A BLOWN MONITOR FUSE, TEST THE PRIMARY INTERLOCK
SWITCH AND MONITOR SWITCH FOR PROPER OPERATION.
If the monitor fuse is blown by improper switch operation, the monitor fuse and the monitor switch must
be replaced with "monitor fuse and switch assembly" part number FFS-BA012WRK0, even if the monitor
switch operates normally. The monitor fuse and switch assembly is packed with 20 ampere fuse and
switch.
H
BLOWN MONITOR FUSE
J
TOUCH CONTROL PANEL ASSEMBLY TEST
The touch control panel consists of circuits including semiconductors such as LSI, ICs, etc. Therefore,
unlike conventional microwave ovens, proper maintenance cannot be performed with only a voltmeter
and ohmmeter.
In this service manual, the touch control panel assembly is divided into two units, Control Unit and Key
Unit, and also the Control Unit is divided into two units, CPU Unit and Power Unit, and troubleshooting
by unit replacement is described according to the symptoms indicated.
1. Key Unit. Note : Check key unit ribbon connection before replacement.
The following symptoms indicate a defective key unit. Replace the key unit.
a) When touching the pads, a certain pad produces no signal at all.
b) When touching a number pad, two figures or more are displayed.
c) When touching the pads, sometimes a pad produces no signal.
2. Control Unit
The following symptoms indicate a defective control unit. Before replacing the control unit, perform
the Key unit test (Procedure K) to determine if control unit is faulty.
2-1 In connection with pads.
a) When touching the pads, a certain group of pads do not produce a signal.
b) When touching the pads, no pads produce a signal.
2-2 In connection with indicators
a) At a certain digit, all or some segments do not light up.
b) At a certain digit, brightness is low.
c) Only one indicator does not light.
d) The corresponding segments of all digits do not light up; or they continue to light up.
e) Wrong figure appears.
f) A certain group of indicators do not light up.
g) The figure of all digits flicker.
2-3 Other possible problems caused by defective control unit.
a) Buzzer does not sound or continues to sound.
b) Clock does not operate properly.
I
NOISE FILTER TEST
Disconnect the oven from power supply.
Disconnect the lead wires from the terminal the noise filter. Using
an ohmmeter, check between the terminals as described in the
following table.
MEASURING POINT
INDICATION OF OHMMETER
Between N and H
Open circuit.
Between terminal N and GRAY
Short circuit.
Between terminal H and RED
Short circuit.
If incorrect reading are obtained, replace the noise filter.
FUSE 20A
NOISE FILTER
NOISE SUPPRESSION COIL
LINE CROSS CAPACITOR
0.22
µ
F / AC 250V
LINE BYPASS
CAPACITOR
0.0033
µ
F / AC 125V
LINE BYPASS
CAPACITOR
0.0033
µ
F / AC 125V
H
RED
GRY
N
