Sharp R-9H56, Service Manual

Page: 19 / 48

R-9H56
17
TEST PROCEDURES (CONT'D)
PROCEDURE
LETTER
COMPONENT TEST
Disconnect the leads from the motor.
Using an ohmmeter, check the resistance between the two terminals as described in the table below.
Table: Resistance of Motor
Motors Resistance
Fan motor Approximately 295
Ω
Turntable motor Approximately 10.5 k
Ω
Convection fan motor Approximately 210
Ω
Damper motor Approximately 11 k
Ω
If incorrect readings are obtained, replace the motor.
CARRY OUT 4R CHECKS.
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 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.
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. Replacethe 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 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.
d) Proper temperature measurement is not obtained.
L TOUCH CONTROL PANEL ASSEMBLY TEST
K MONITOR RESISTOR TEST
CARRY OUT 3D CHECKS.
Disconnect the leads from the monitor resist. Using an ohmmeter and set on a low range. Check between
the terminals of the monitor resistor.
The resistance of monitor resistor is approx. 0.8 ohms.
If incorrect readings are obtained, replace the monitor resistor.
CARRY OUT 4R CHECKS.