R-7N76(W)M
R-7N76(B)M
17
COMPONENT TEST
TEST PROCEDURES (CONT'D)
PROCEDURE
LETTER
N
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 troubleshooting by replacement is described according to the symptoms indicated.
1. Key Unit
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. Replacing the 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.
d) Proper temperature measurement is not obtainned.
O
KEY UNIT TEST
If the display fails to clear when the STOP/CLEAR pad is depressed, first verify the flat ribbon is making
good contact, verify that the door sensing switch (stop switch) operates properly; that is the contacts are
closed when the door is closed and open when the door is open. If the door sensing switch (stop switch)
is good, disconnect the flat ribbon cable that connects the key unit to the control unit and make sure the
door sensing switch is closed (either close the door or short the door sensing switch connecter). Use the
Key unit matrix indicated on the STOP/CLEAR pad making momentary contact. If the control unit
responds by clearing with a beep the key unit is faulty and must be replaced. If the control unit does not
respond, it is a faulty and must be replaced. If a specific pad does not respond, the above method may
be used (after clearing the control unit) to determine if the control unit or key pad is at fault.
G12
G11
G10
G8
G1
G2
G3
G4
G5
G6
G7
KEY UNIT
GRILL
10
MIN.
1
MIN.
10
SEC.
CONVEC
TION
TEMP
DUAL
CONVECTION
/GRILL
LOGICOOK
FOOD
Kg • Lb
Kg / Lb
LESS
MORE
g • oz
LOGICOOK
DRINK
STOP
/CLEAR
TIMER
/HOLD
MICROWAVE
POWER
LEVEL
AUTO
MINUTE
/START
AUTO
START
AUTO
COOK
AUTO
DEFROST
G9
