R200K
8 – 4
[10] Procedure J: HIGH VOLTAGE FUSE TEST
CARRY OUT 3D CHECKS.
If the high voltage fuse is blown, there could be a short in the high voltage rectifier or the magnetron.
Check them and replace the defective parts and the high voltage fuse.
CARRY OUT 4R CHECKS.
CAUTION: ONLY REPLACE HIGH VOLTAGE FUSE WITH THE CORRECT VALUE REPLACEMENT.
[11] Procedure K: 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.
1) When touching the pads, a certain pad produces no signal at all.
2) When touching a number pad, two figures or more are displayed.
3) 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 L) to determine if
control unit is faulty.
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) 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 up.
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.
3) Other possible troubles 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.
[12] Procedure L: KEY UNIT (MEMBRANE SWITCH) TEST
1. CARRY OUT 3D CHECKS.
2. Isolate the key unit with the control panel frame to be tested.
3. Using an ohmmeter and referring to the key unit matrix indicated on the control unit circuit, check the circuit between the pins of the key unit that
correspond to the STOP/CLEAR pad. When the pad is pressed, the ohmmeter should indicate short circuit. When the pad is released, the ohmme-
ter should indicate open circuit. If incorrect readings are obtained, the key unit is faulty and must be replaced. About the other pads, the above
method may be used.
4. CARRY OUT 4R CHECKS.
Pin NO. G1
Pin NO. G10
Key unit ribbon
cable
Key unit (Membrane Switch) front view
G4
G5
G6
G1
G8
G9
G10
G2
G3
G7
6
3
9
TIMER
CLOCK
2
5
0
8
4
1
7
INSTANT COOK
EASY
DEFROST
FROZEN
VEGETABLES
JACKET
POTATO
BEVERAGE
DINNER
PLATE
POWER
LEVEL
EXPRESS
DEFROST
FRESH
VEGETABLES
STOP
CLEAR
START
