Sharp R-15AM Service Manual page 15

PROCEDURE
LETTER
H NOISE FILTER TEST
CARRY OUT 3D CHECKS.
Disconnect the leads from the terminals of noise filter.
Using an ohmmeter, check between the terminals as described
in the following table.
MEASURING POINTS
Between N and L
Between terminal N and WHITE
Between terminal L and RED
If incorrect readings are absorbed, replace the noise filter unit.
CARRY OUT 4R CHECKS.
I MOTOR WINDING TEST
CARRY OUT 3D CHECKS.
Disconnect the leads from the motor. Using an ohmmeter, check the resistance between the two
terminals as described in the table below.
If incorrect readings are obtained, replace the motor.
CARRY OUT 4R CHECKS.
J HIGH VOLTAGE FUSE F2 TEST
CARRY OUT 3D CHECKS.
If the high voltage fuse F2 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 F2.
CARRY OUT 4R CHECKS.
CAUTION:
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 can not be performed with only a voltmeter
and ohmmeter.
In this service manual, the touch control panel assembly is in one unit and troubleshooting by unit
replacement is described according to the symptoms indicated.
Control Panel.
The following symptoms indicate a defective control unit.
1. Tact Switch.
The following symptoms indicate a defective tact switch. Replace the tact switch.
a) When touching a tact switch, a certain tact switch produces no signal at all.
b) When touching a tact switch, sometimes a tact switch produces no signal.
2. In connection with tact switches.
a) When touching a tact switch, a certain group of tact switch do not produce a signal.
b) When touching a tact switch, no tact switch produce a signal.
3. Display problems.
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.
TEST PROCEDURES
INDICATION OF OHMMETER
Approx. 680 kΩ
Short circuit
Short circuit
Table: Resistance of Motor
Motors
Fan motor
Antenna motor
Only replace high voltage fuse with the correct value replacement.
COMPONENT TEST
WHT
Resistance
Approximately 219 Ω
Approximately 11 kΩ
13
N
F1: FUSE
F10A
DISCHARGE RESISTOR 680 kΩ 1/2W
NOISE SUPPRESSION COIL
LINE CROSS CAPACITOR 0.22µF/ AC 250V
LINE BYPASS LINE BYPASS
CAPACITOR CAPACITOR
0.0033µF/ AC 250V 0.0033µF/ AC 250V
DISCHARGE
RESISTOR 10MΩ 1/2W
R-15AM
L
RED