15
R-320HK
R-320HQ
R-320HW
TEST PROCEDURES
PROCEDURE
LETTER
COMPONENT TEST
CAUTION: BEFORE REPLACING A BLOWN C/T FUSE, TEST THE PRIMARY INTERLOCK RELAY,
SECONDARY INTERLOCK SWITCH, DOOR SENSING SWITCH AND MONITOR SWITCH
FOR PROPER OPERATION.
If the C/T fuse is blown by improper switch operation, the C/T fuse and monitor switch must be replaced with
"C/T fuse and monitor switch assembly" part number FFS-BA034WRKZ, even if the monitor switch operates
normally. The C/T fuse and monitor switch assembly is comprised of a 20 ampere fuse and switch.
A continuity check across the C/T fuse terminals should indicate a closed circuit unless the temperature of the
C/T fuse reaches approximately 302˚F(150˚C).
An open C/T fuse indicates overheating of the magnetron. Check for restricted air flow to the magnetron,
especially the cooling fa air guide.
CAUTION: IF THE C/T FUSE INDICATES AN OPEN CIRCUIT AT ROOM TEMPERATURE, REPLACE
THE C/T FUSE.
5. Reconnect all leads removed from components during testing.
6. Reinstall the outer case (cabinet).
7. Reconnect the power supply cord after the outer case is installed.
8. Run the oven and check all functions.
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, LSI Unit and Power Unit, and troubleshooting by unit
replacement is described according to the symptoms indicated.
Before testing,
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 transformer.
5) Ensure that these leads remain isolated from other components and oven chassis by using insulation tape.
1. Key Unit.
NOTE ;
1) Re-install the outer case (cabinet).
2) Reconnect the power supply cord after the outer case is installed.
3) Run the oven and check all functions.
The following symptoms indicate a defective 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.
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.
c) Cooking is not possible.
I
TOUCH CONTROL PANEL ASSEMBLY TEST
