Sharp R-22AT CARRY OUT 4R CHECKS, J Motor Winding Test, K Noise Filter Test, Test Procedures

Models: R-22AT R-24AT

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3. CARRY OUT 4R CHECKS.
NOISE FILTER

R-22AT

R-24AT

 

TEST PROCEDURES

PROCEDURE

 

LETTER

COMPONENT TEST

 

If the meter does not indicate above resistance, replace the thermistor.

 

3. CARRY OUT 4R CHECKS.

JMOTOR WINDING TEST

CARRY OUT 3D CHECKS.

Disconnect the leads from the motor. Using an ohmmeter, check the resistance between the two terminals.

Resistance of Blower motor should be approximately 60.

Resistance of Antenna motor should be approximately 8.8 k.

If incorrect readings are obtained, replace the motor.

CARRY OUT 4R CHECKS.

KNOISE 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 POINT

INDICATION OF OHMMETER

Between N and L

Approx. 680 k

 

 

Between terminal N and WHIT

Short circuit

 

 

Between terminal L and BLK

Short circuit

If incorrect readings are absorbed, replace the noise filter.

CARRY OUT 4R CHECKS.

N

L

 

F3 : WEAK POINT

 

NOISE SUPPRESSION COIL

DISCHARGE RESISTOR 680 k1/2W

LINE CROSS CAPACITOR 0.22F/ AC250V

 

DISCHARGE RESISTOR 10 M1/2W

LINE CROSS CAPACITOR

LINE CROSS CAPACITOR

10000 pF/ AC250V

10000 pF/ AC250V

WHT

BLK

LHIGH VOLTAGE FUSE F4, F5 TEST CARRY OUT 3D CHECKS.

If the high voltage fuse F4 (or F5) is blown, there could be a short in the high voltage rectifier or the magnetron MG1 (or MG2). Check them and replace the defective parts and the high voltage fuse F4 (or F5).

CARRY OUT 4R CHECKS.

CAUTION: Only replace high voltage fuse with the correct value replacement.

MTOUCH CONTROL PANEL ASSEMBLY TEST

The touch control panel consists of circuits including semiconductors such as LSI, IC, 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, 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 the pads, sometimes a pad produces no signal.

2.Control Unit

The following symptoms may indicate a defective control unit. Replacing the control unit. Before replacing the control unit, perform the key unit test (Procedure N) to determine if control unit is faulty.

2-1 Programming problems.

a)When touching the pads, a certain group of pads do not produce a signal. 2-2 Display problems.

a)For a certain digit, all or some segments do not light up.

b)For 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.

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Sharp R-22AT CARRY OUT 4R CHECKS, J Motor Winding Test, K Noise Filter Test, M Touch Control Panel Assembly Test, Letter