Sharp R-2277 Service Manual page 16

R-2277
R-2287
PROCEDURE
LETTER
J MONITOR RESISTOR TEST
CARRY OUT 3D CHECKS.
Disconnect the leads from the monitor resistor. Using an ohmmeter and set on a low range. Check
between the terminals of the monitor resistor.
If incorrect readings are obtained, replace the monitor resistor.
CARRY OUT 4R CHECKS.
K MAGNETRON THERMISTOR TEST
CARRY OUT 3D CHECKS.
Disconnect connector-H from the CPU unit. Measure the resistance of the thermistor with an
ohmmeter. Connect the ohmmeter leads to the leads of the thermistor.
If the meter does not indicate above resistance, replace the thermistor.
CARRY OUT 4R CHECKS.
EXHAUST THERMISTOR TEST
CARRY OUT 3D CHECKS.
Disconnect connector-B from the CPU unit. Measure the resistance of the thermistor with an
ohmmeter. Connect the ohmmeter leads to the leads of the thermistor.
If the meter does not indicate above resistance, replace the thermistor.
CARRY OUT 4R CHECKS.
INTAKE THERMISTOR TEST
CARRY OUT 3D CHECKS.
Disconnect connector-D from the CPU unit. Measure the resistance of the thermistor with an
ohmmeter. Connect the ohmmeter leads to the leads of the thermistor.
If the meter does not indicate above resistance, replace the thermistor.
CARRY OUT 4R CHECKS.
L MOTOR WINDING TEST
CARRY OUT 3D CHECKS.
Disconnect the leads from the motor. Using an ohmmeter, check the resistance between the two
terminals.
TEST PROCEDURES
COMPONENT TEST
The resistance of monitor resistor should be read approx. 4.3Ω.
Room Temp.
15˚C ........................ Approx. 15.91 kΩ
20˚C ........................ Approx. 13.04 kΩ
25˚C ........................ Approx. 10.74 kΩ
Room Temp.
15˚C ........................ Approx. 77.45 kΩ
20˚C ........................ Approx. 61.47 kΩ
25˚C ........................ Approx. 49.12 kΩ
Room Temp.
15˚C ........................ Approx. 15.88 kΩ
20˚C ........................ Approx. 13.03 kΩ
25˚C ........................ Approx. 10.74 kΩ
14
Resistance
Resistance
Resistance