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MICROWAVE OVEN
PROCEDURE
LETTER
H
BLOWN MONITOR FUSE TEST
1.
Disconnect power supply cord and remove outer cabinet case.
2.
Open door and block it open.
3.
Discharge high-voltage capacitor.
4.
If the monitor fuse is blown when the door is opened, check primary interlock relay as described earlier. If
primary interlock relay indicates proper operation, replace the the complete Latch Hook/Switch Assembly.
5.
Reconnect all leads removed from components during testing.
6.
Reinstall the outer cabinet case, then reconnect power supply cord.
7.
Run the oven and check all functions.
I
TOUCH CONTROL PANEL ASSEMBLY TEST
NOTE: The touch control panel consists of circuits including semiconductors such as LSI, ICS, etc. Therefore,
unlike conventional microwave ovens, proper troubleshooting 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 the Control Unit is divided into two units, LSI Unit and Power Unit. Troubleshooting by unit
replacement is described according to the symptoms indicated.
Before Testing:
1.
Disconnect power supply cord and remove outer cabinet case.
2.
Open door and block it open.
3.
Discharge high-voltage capacitor.
4.
Disconnect the leads to the primary of the power transformer and ensure that these leads remain isolated
from other components and oven chassis by using insulation tape.
5.
Re-connect the power supply cord.
KEY UNIT
1.
Disconnect power supply cord and remove outer cabinet case.
2.
Open door and block it open.
3.
Discharge high-voltage capacitor.
4.
Check Key Unit ribbon connection before replacement.
5.
Reconnect all leads removed from components during testing.
6.
Reinstall the outer cabinet case, then reconnect power supply cord.
7.
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.
If the Key unit is defective.
1.
2.
3.
4.
5.
6.
7.
CONTROL UNIT
The following symptoms may indicate a defective control unit. Before replacing the control unit, perform the
Key Unit test (Procedure J) to determine if control unit is faulty.
a. In connection with pads.
1.
2.
b. In connection with indicators
1.
2.
3.
P P
r r
i i
o o
r r
t t
o o
S S
e e
P P
r r
i i
o o
r r
t t
o o
S S
e e
TEST PROCEDURES
Disconnect power supply cord and remove outer cabinet case.
Open door and block it open.
Discharge high-voltage capacitor.
Replace the Key Unit.
Reconnect all leads removed from components during testing.
Reinstall the outer cabinet case, then reconnect power supply cord.
Run the oven and check all functions.
When touching the pads, a certain group of pads do not produce a signal.
When touching the pads, no pads produce a signal.
At a certain digit, all or some segments do not light up.
At a certain digit, brightness is low.
Only one indicator does not light.
r r
i i
a a
l l
N N
u u
m m
b b
e e
r r
1 1
2 2
0 0
0 0
1 1
r r
i i
a a
l l
N N
u u
m m
b b
e e
r r
1 1
2 2
0 0
0 0
1 1
Troubleshooting & Technical Data
COMPONENT TEST
6-7
5 5
4 4
5 5
4 4
(CONTINUED)
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